Concretion promoting material, method for improving soil, and sealing material

Abstract

A concretion promoting material according to the present invention comprises: an ion supply material that gradually releases ions that enable formation of a hardly soluble compound; and an acid that donates protons.

Description

Concretion accelerator, ground improvement method, and sealing material CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is based on Japanese Patent Application No. 2024-53423 filed on March 28, 2024, and Japanese Patent Application No. 2024-230570 filed on December 26, 2024, and claims the benefit of priority thereto, the entire contents of which are incorporated herein by reference.

[0002] The present disclosure relates to a concretion accelerator, a ground improvement method, and a sealing material.

[0003] When constructing a structure on soft ground such as clay or permeable ground such as sandy soil, it is necessary to improve the strength and permeability of the ground.

[0004] Patent Document 1 discloses a method of improving soft ground in which a hole for injecting chemicals is excavated in the soft ground, a chemical whose main component is limestone is injected to cause moisture absorption and solidification, and a carbon dioxide-generating hardening agent is then injected to quickly harden the limestone component.

[0005] Patent Document 2 discloses a technology for improving the ground by injecting organic nutrient sources, calcium salts, and a pH buffer, and utilizing carbon dioxide gas generated when microorganisms metabolically decompose the organic nutrient sources, or pH fluctuations caused by metabolism.

[0006] Patent Document 3 discloses a technique in which a first aqueous solution rich in calcium ions and a second aqueous solution containing carbonate ions are injected into a target water-stopping location, and calcium carbonate precipitate is deposited at the target water-stopping location.

[0007] Japanese Patent Application Laid-Open No. 52-126909 Japanese Patent Application Laid-Open No. 2006-169940 Japanese Patent Application Laid-Open No. 2006-249294

[0008] In order to improve the ground to have better strength and water-stopping properties, technology is needed that can further improve the efficiency of ground improvement and maintain the effects of ground improvement for a longer period of time.

[0009] The present disclosure has been made in view of such problems, and its purpose is to improve techniques for improving ground.

[0010] In order to solve the above problems, a concretion accelerator according to one embodiment of the present disclosure comprises an ion supplier that gradually releases ions capable of forming a poorly soluble compound, and an acid that donates protons.

[0011] Another aspect of the present disclosure is a method for improving ground, comprising the steps of reducing the permeability of the ground and supplying an ion supply material to the ground to supply ions capable of forming a sparingly soluble compound.

[0012] Yet another aspect of the present disclosure is a ground improvement method, comprising the steps of: acquiring an index representing the permeability of the target ground; and, if the permeability of the ground is such that ions capable of forming sparingly soluble compounds supplied to the ground may become supersaturated, supplying an ion supplying material to the ground for supplying ions.

[0013] Yet another aspect of the present disclosure is a method for improving ground, comprising the steps of supplying, to the ground, an ion supplying material that slowly releases ions capable of forming a sparingly soluble compound, and supplying, to the ground, an acid that donates protons.

[0014] Yet another aspect of the present disclosure is a method for improving ground, comprising the steps of reducing the permeability of the ground, supplying the ground with an ion supplying material that slowly releases ions capable of forming a sparingly soluble compound, and supplying the ground with an acid that donates protons.

[0015] Yet another aspect of the present disclosure is a sealant, which includes an ion donor that slowly releases ions capable of forming a poorly soluble compound, and an acid that donates protons.

[0016] According to the present disclosure, it is possible to improve techniques for improving ground.

[0017] Fig. 1 is a flowchart showing the procedure of a ground improvement method according to a first embodiment of the present disclosure. Fig. 2 is a diagram showing examples of additives added to a concretion accelerator. Fig. 3 is a flowchart showing the procedure of a ground improvement method according to a first embodiment of the present disclosure. Fig. 4 is a diagram for explaining the procedure of the ground improvement method shown in Fig. 3. Fig. 5 is a diagram showing the results of a water permeability test. Fig. 6 is a flowchart showing the procedure of a method for using a building material according to a second embodiment of the present disclosure.

[0018] First Embodiment As a first embodiment of the present disclosure, a technique for improving ground (including bedrock, soil, etc.) will be described. In the ground improvement method of the present disclosure, an ion supplying material for supplying ions that form poorly soluble compounds such as calcium carbonate is supplied to the ground, and the poorly soluble compounds are precipitated in voids in the ground, thereby blocking the voids.

[0019] It is known that extremely dense and hard lumps of calcium carbonate called concretions are often found in sedimentary rock strata. These concretions often contain fossils inside. Concretions have been found in strata that are tens of thousands to tens of millions of years old, and in most cases, they remain untouched and retain their spherical shape, even when the surrounding rocks and strata have weathered due to long-term exposure to the natural environment. The fossils inside are also in extremely good condition, and have been found to have been preserved with almost no alteration for tens of millions of years.

[0020] Research by the present inventors has shown that concretions are formed when the carbon components that made up the body tissues of organisms contained as fossils are converted into bicarbonate ions (HCO ３ －It has been revealed that concretions are formed when bicarbonate ions, which are carbon components that make up the organism's body, leak out from the mouth or other organs, then diffuse into the surrounding strata due to a concentration gradient, react with calcium ions present in the strata, and precipitate as calcium carbonate, which has low solubility in water. Through this mechanism, concretions rapidly grow spherically around the organ where the carbon components that make up the organism's body leak out as bicarbonate ions, quickly forming a chemically stable and dense barrier around the organism that does not weather even when exposed to the natural environment, preserving the fossils of the organisms inside in extremely good condition for tens of millions of years.

[0021] The ground improvement method of the present disclosure applies this mechanism by supplying ions that form poorly soluble compounds from an ion supplying material to the ground, and then precipitating the poorly soluble compounds from the ions that have diffused in the ground, thereby artificially forming dense concretions in the ground, which can dramatically improve the strength and water-stopping ability of the ground.

[0022] For example, when concreting the ground by precipitating calcium carbonate, bicarbonate ions or carbonate ions may be supplied to the ground from an ion supply material, similar to concretions. In this case, calcium carbonate is formed from bicarbonate ions or carbonate ions supplied from the ion supply material and calcium ions present in the ground. Contrary to concretions, calcium ions may be supplied to the ground from an ion supply material. In this case, calcium carbonate is formed from calcium ions supplied from the ion supply material and bicarbonate ions or carbonate ions present in the ground. Both bicarbonate ions or carbonate ions and calcium ions may be supplied from the ion supply material. In this case, an ion supply material that supplies bicarbonate ions or carbonate ions and an ion supply material that supplies calcium ions may be supplied to the ground.

[0023] The ion supply material of the present disclosure is configured to be capable of gradually releasing ions capable of forming a poorly soluble compound. The ion supply material includes a base material that coats or supports a compound containing ions that form the poorly soluble compound. The base material is made of a material that allows the ions to gradually leach out. For example, the base material may be a thermoplastic resin, a thermosetting resin, cement, or the like. This allows the ions to diffuse over a wide area in the ground, causing the poorly soluble compound to precipitate and block voids. Furthermore, the effect of improving the ground can be sustained for a long period of time.

[0024] In the present disclosure, "sustained release" does not mean that the entire amount of ions that the ion supply material can supply is released during or immediately after application of the ion supply material, resulting in a loss of the ion-releasing function, but rather that the ions that the ion supply material can supply remain even after a certain period of time has passed since application of the ion supply material, thereby maintaining the ion-releasing function. This "certain period" is longer than the timescale (approximately 6 hours) from preparation of the ion supply material to completion of application of the ion supply material. The ratio of the amount of ions released within 6 hours of application of the ion supply material to the total amount of ions that the ion supply material can release is preferably 5% or less, more preferably 1% or less, when the ion supply material has a non-aqueous base material such as a curable resin, and preferably 20% or less, more preferably 5% or less, when the ion supply material has a hydrous base material such as cement milk. The "certain period" is longer than the timescale required for the completion of hardening of the base material, such as the curable resin that is the base material of the ion supply material or the cement milk that serves as a carrier when the ion supply material is applied (approximately 10 days for a curable resin base material, and approximately 48 days for a cement-based base material). The ratio of the amount of ions released from the application of the ion supply material until the above-mentioned period has elapsed to the total amount of ions that the ion supply material of the present disclosure can release is preferably 20% or less, more preferably 5% or less, when the ion supply material has a non-aqueous base material such as a curable resin, and preferably 90% or less, more preferably 20% or less, when the ion supply material has a hydrous base material such as cement milk. The "certain period" may be the same as or shorter than the timescale required for the formation of natural concretions (for example, several years, depending on the size of the concretions). When water such as groundwater is present at the location where the ion supply material is applied, the ratio of the amount of ions released within one year after the ion supply material is applied to the total amount of ions that the ion supply material of the present disclosure can release is preferably 50% or less, more preferably 100% or less. When no water is present at the location where the ion supply material is applied, the amount of ions released from the ion supply material may be substantially 0% even 100 years after the ion supply material is applied.In other words, when the ion supply material is installed, if there are already fine cracks or voids that the base material cannot reach and groundwater is flooding the area, ions will be released from the ion supply material to block the cracks and voids, forming dense and robust artificial concretions; and if there are no cracks or voids in the surrounding area and no groundwater is present when the ion supply material is installed, the ions will not be released from the ion supply material but will remain in the ion supply material, and it is preferable that the effect of ions being released when cracks or voids occur and blocking the cracks and voids will be permanent.

[0025] In the ion supply material, the form of the ion supply material, the type of base material, the water content, the type of ion-containing compound, the particle size, the surface area, the content ratio of the base material to the compound, etc. are selected so that the sustained release property as described above is satisfied. The ion-containing compound is preferably readily soluble in water. If the pH of an aqueous solution in which the compound is dissolved in water is low, the equilibrium between carbonate ions and bicarbonate ions in the aqueous solution will shift toward bicarbonate ions, making it difficult for calcium carbonate to precipitate, so it is preferable that the aqueous solution in which the compound is dissolved in water be alkaline.

[0026] The rate at which ions are released from an ion supplying material can be measured as follows. The first method involves collecting a base material (a hardened resin or a hardened cement body) from a location where an ion supplying material has been applied, measuring the distribution of Ca ions, Na ions, etc. in a sample collected from the construction site and a blank sample to which no ion supplying material has been applied using X-rays or the like, and calculating the cumulative area. The second method involves, when the base material is organic, burning and incinerating a sample collected from the construction site, and then measuring the metal ions contained therein using high-frequency inductively coupled plasma (ICP) atomic emission spectroscopy or the like. The third method involves, when the ion supplying material is in the form of microcapsules or the like, measuring the voids in a sample collected from the construction site using a scanning electron microscope (SEM) or the like.

[0027] When a proton-donating acid is supplied in addition to an ion supplying material, the calcium contained in rocks in the ground and cement of structures is eluted as calcium ions by the action of the acid, allowing more calcium carbonate to precipitate and promoting concretion of the ground. Therefore, the concretion accelerator of the present disclosure includes an ion supplying material that gradually releases ions capable of forming a sparingly soluble compound, and an acid that donates protons.

[0028] The ion supply material may be configured so that the acid is gradually released from the ion supply material. That is, rather than all of the protons contained in the ion supply material being released during or immediately after the application of the ion supply material and losing the proton-releasing function, the ion supply material may be configured so that protons that can be supplied remain even after a certain period of time has passed since the application of the ion supply material, thereby maintaining the proton-releasing function. The "certain period" may be the same as or shorter than the time scale until natural concretions are formed (for example, several years, depending on the size of the concretions). When water such as groundwater is present at the site where the ion supply material is applied, the ratio of the amount of protons released within one year after the application of the ion supply material to the total amount of protons that the ion supply material of the present disclosure can release is preferably greater than the ratio of the amount of ions released within one year after the application of the ion supply material to the total amount of ions that the ion supply material can release. When water is not present at the site where the ion supply material is applied, the amount of protons released from the ion supply material may be substantially 0% even 100 years after the application of the ion supply material. In other words, when the ion supply material is installed, if there are already tiny cracks or voids that the base material cannot reach and groundwater is flooding the area, protons will be released from the ion supply material, eluting calcium ions contained in the surrounding bedrock, strata, structures, etc., to form dense and robust artificial concretions; and if there are no cracks or voids in the surrounding area when the ion supply material is installed and there is no groundwater, it is preferable that the protons will not be released from the ion supply material but will remain in the ion supply material, and when cracks or voids occur, the protons will be released and the effect of sealing the cracks and voids will be permanent.

[0029] The form of the ion supplying material, the type of base material, the water content, the type of acid, the particle size, the surface area, the content ratio of the base material and the acid, and the like are selected so that the sustained release properties described above are satisfied. The dissolution (diffusion) rate of the acid is preferably faster than that of calcium oxide or hydroxide, or carbonate or bicarbonate. This increases the amount of ions per unit period, thereby promoting concretion. When the ion supplying material is applied to a cement-based structure, the dissolution rate of the acid should be faster than the rate at which calcium hydroxide contained in the cement is leached by water. The solubility of the acid is preferably higher than that of calcium carbonate. If the pH of the aqueous solution in which the acid is dissolved in water is too low, the equilibrium between carbonate ions and bicarbonate ions in the aqueous solution will shift toward bicarbonate ions, making it difficult for calcium carbonate to precipitate. Therefore, it is preferable that the diffusion of water is greater than the diffusion of acid in the area where the ion supplying material is applied.

[0030] Hereinafter, for the sake of simplicity, the ion supply material and the concretion accelerator will be collectively referred to as the “ion supply material.” That is, the “ion supply material” in the following description may refer to only the ion supply material, may refer to only the concretion accelerator, or may refer to both the ion supply material and the concretion accelerator.

[0031] In ground with high permeability, groundwater flows into the voids in the ground before ions supplied from the ion supply material injected into the ground precipitate as poorly soluble compounds. This dilutes the ions without reaching a supersaturated state, potentially preventing effective precipitation of the poorly soluble compounds. To solve this problem, the method disclosed herein reduces the permeability of the ground in advance by injecting an improvement material or the like into the ground to improve the ground, and then supplies the ion supply material to the ground. This increases the concentration of ions supplied from the ion supply material supplied to the ground, creating a supersaturated state, thereby effectively precipitating the poorly soluble compounds and blocking the voids. In ground with inherently low permeability, the ion supply material may be supplied without ground improvement using an improvement material or the like. Furthermore, in the method disclosed herein, the permeability of the ground may be reduced, and then the improvement material and the ion supply material may be supplied simultaneously to increase the concentration of ions supplied from the ion supply material.

[0032] FIG. 1 is a flowchart showing the steps of a ground improvement method according to a first embodiment of the present disclosure.

[0033] The contractor obtains an index representing the permeability of the ground to be constructed (S10). The contractor may conduct an on-site permeability test to obtain the index, or may obtain an index representing the permeability of the surveyed ground from an investigator. The on-site permeability test may be a transient method in which a strainer section (test section) into which groundwater flows is provided at the end of a borehole in the ground, and the water level in the borehole is artificially lowered or raised, and the permeability coefficient of the ground is determined from the change in the groundwater level. Alternatively, the on-site permeability test may be a steady method in which the permeability coefficient of the ground is determined from the flow rate when the water level in the measuring pipe becomes constant after pumping or pouring water. The index representing the permeability may be a static diffusion coefficient or a dynamic permeability coefficient. The diffusion coefficient may be converted to the permeability coefficient. On the other hand, the permeability coefficients of the concretion accelerator and the ion supply material can be measured using a solidified test specimen, or calculated from the permeability coefficient or diffusion coefficient of the base material and the mixed amount of the ion supply material and acid. Hereinafter, the case of obtaining the hydraulic conductivity will be described.

[0034] If the obtained permeability coefficient is equal to or greater than a predetermined value (Y in S12), the contractor supplies an improvement material to the ground to reduce the permeability coefficient of the ground to less than a predetermined value (S14). This predetermined value may be an upper limit of the permeability coefficient at which ions capable of forming poorly soluble compounds supplied from the ion supply material injected into the ground can become supersaturated in the ground. The predetermined value may be, for example, 1×10 －２ m / sec, 1 x 10 －３ m / sec, 1 x 10 －４ m / sec, 1 x 10 －５ m / sec, 1 x 10 －６ m / sec, 1 x 10 －７ m / sec, 1 x 10 －８ m / sec, 1 x 10 －９ It may also be m / sec.

[0035] The improvement material may be any known improvement material, such as cement or cement-based improvement material, lime or lime-based improvement material, polymer-based improvement material, or composite improvement material containing any of these. An improvement material injection hole for injecting the improvement material into the ground may be excavated, and the improvement material may be injected into the improvement material injection hole. The surface layer of the ground may be excavated, mixed with the improvement material, and then backfilled. The improvement material may also serve as an ion supply material. In this case, the improvement material contains ions that form a sparingly soluble compound. The improvement material may also contain an ion supply material. For example, the improvement material may be a powdered ion supply material mixed into cement or the like.

[0036] After the ground has been improved, the process returns to step S10, and the permeability coefficient of the ground is again obtained (S10). If the permeability coefficient of the improved ground is equal to or greater than the predetermined value (Y in S12), the improvement material is again injected into the ground to reduce the permeability coefficient of the ground to below the predetermined value (S14).

[0037] If the permeability coefficient of the ground is less than a predetermined value (N in S12), the constructor supplies an ion supply material to the ground (S16). An ion supply material injection hole for injecting the ion supply material into the ground may be excavated, and the ion supply material may be injected into the ion supply material injection hole. The surface layer of the ground may be dug up, the ion supply material may be mixed in, and then the ground may be backfilled.

[0038] The ion supplying material supplies ions capable of forming a poorly soluble compound. The poorly soluble compound may be, for example, calcium carbonate. The poorly soluble compound may be any compound as long as it has a sufficiently low solubility in water at the temperature of the environment in which the ion supplying material is disposed, is chemically stable, and does not pollute the surrounding natural environment. For example, carbonates such as calcium carbonate and iron (II) carbonate (siderite, siderite), calcium magnesium carbonate (CaMg(CO ３ ) ２ The inorganic salts may be double salts such as calcium sulfate, dolomite, and dolomite, sulfates such as calcium sulfate, and sulfides such as iron sulfide (FeS).

[0039] The ion supplying material may contain a first compound capable of generating cations that form a poorly soluble salt. When calcium carbonate is to be precipitated as the poorly soluble compound, the ion supplying material may contain a first compound capable of generating calcium ions. The first compound may be an inorganic calcium salt, an organic calcium salt, a calcium compound, or the like. The inorganic calcium salt may be calcium chloride (CaCl ２ ), calcium nitrate (Ca(NO ３ ) ２ ), calcium hydrogen carbonate (bicarbonate) (Ca(HCO ３ ) ２ ) and the like. The calcium compound may be calcium oxide, calcium hydroxide, and the like. The calcium organic acid salt may be calcium acetate, calcium lactate, calcium formate, and the like. The first compound may be cement and its hardened product, mortar and its hardened product, concrete, and the like.

[0040] The ion supplying material may contain a second compound capable of generating an anion that forms a poorly soluble salt. When calcium carbonate is to be precipitated as the poorly soluble compound, the ion supplying material may contain a second compound capable of generating at least one of carbonate ions and bicarbonate ions. The second compound may be, for example, sodium bicarbonate (NaHCO ３ ), potassium bicarbonate (KHCO ３ ), ammonium bicarbonate (NH ４ HCO ３ ), magnesium carbonate (MgCO３ ) etc.

[0041] The ion supplying material may contain a third compound that generates carbon dioxide by chemical reaction as a carbonate source for precipitating calcium carbonate. The third compound may be a carbonate ester, a cyclic carbonate, or the like.

[0042] The carbonate ester may be dimethyl carbonate, diethyl carbonate, diphenyl carbonate, ethylene carbonate, propylene carbonate, 1,3-dioxan-2-one, 4-fluoro-1,3-dioxolan-2-one, 4-chloro-1,3-dioxolan-2-one, 4-vinyl-1,3-dioxolan-2-one, 4-methoxy-1,3-dioxolan-2-one, vinylene carbonate, or the like.

[0043] The cyclic carbonate may be an ester of carbonic acid and a dihydric or higher alcohol. １ (OH) ２ , R ２ C(OH)C(OH)R ３ , R ４ C(OH)CR ５ C(OH)R ６ , R ７ C(OH)R ８ C(OH)R ９ etc. １ ~R ９ may be a hydrogen atom, a hydroxy group, or a hydrocarbon group having 1 to 6 carbon atoms, and at least one of the hydrogen atoms of the hydrocarbon group may be substituted with a hydroxy group. １ ~R ９ may contain a carbon-carbon double bond. The dihydric or higher alcohol may be glycerin, erythritol, 1,2,4-butanetriol, and the like.

[0044] The cyclic carbonate may be glycerol 1,2-carbonate, glycerol 1,3-carbonate, or a derivative thereof.

[0045] The cyclic carbonate may be an 8-membered or smaller ring, a 7-membered or smaller ring, a 6-membered or smaller ring, or a 5-membered or smaller ring. The cyclic carbonate may be a 3-membered or larger ring, a 4-membered or larger ring, a 5-membered or larger ring, a 6-membered or larger ring, or a 7-membered or larger ring. This allows for stable generation of carbon dioxide.

[0046] The cyclic carbonate may have a hydroxy group. The cyclic carbonate may have one or more, two or more, or three or more hydroxy groups. The cyclic carbonate may have four or fewer, three or fewer, or two or fewer hydroxy groups.

[0047] Cyclic carbonates generally undergo ring-opening via a nucleophilic reaction at the carbonyl carbon with a nucleophile having a hydroxyl group. When the cyclic carbonate has a hydroxyl group, the product of the ring-opening reaction also has a hydroxyl group and can function as a nucleophile. In this case, the ring-opening addition reaction proceeds sequentially, and a ring-opening addition polymerization compound (polymer or oligomer) can be produced. This reaction is promoted in the presence of a base catalyst; therefore, the ring-opening reaction is promoted when the ion supply material contains a base such as calcium hydroxide or a basic oxide such as calcium oxide, or when a base such as calcium hydroxide or a basic oxide such as calcium oxide is present around the ion supply material. The ion supply material may contain a base such as calcium hydroxide, a basic oxide such as calcium oxide, or another basic compound.

[0048] Carbonates generally undergo decarboxylation. The products of the ring-opening reactions described above can also undergo hydrolysis to produce carbon dioxide and an alcohol (e.g., glycerin in the case of glycerol carbonate) or an ether.

[0049] The ion donor may include polymers, oligomers, alcohols, ethers, etc. produced by ring-opening addition polymerization or decarboxylation of cyclic carbonates.

[0050] At least a portion of the carbon dioxide generated from the carbonate ester or cyclic carbonate reacts with calcium ions to generate calcium carbonate. During this process, the calcium carbonate phases are thought to bond (adhere) in a complex manner, incorporating the surrounding base material, soil, sand, etc., to form a strong bond. This allows a hardened body with high compressive strength to be formed around the ion supply material, further strengthening the ground.

[0051] The ion supply material may contain an acid. The acid may be an inorganic acid, an organic acid, a salt of a strong acid and a weak base, a solid acid, or the like. The inorganic acid may be hydrochloric acid, sulfuric acid, nitric acid, or the like. The acid may not contain phosphoric acid. The organic acid may be acetic acid, citric acid, formic acid, oxalic acid, ascorbic acid, or the like. The salt of a strong acid and a weak base may be ammonium chloride, or the like. The solid acid may be a Brønsted acid capable of donating a proton or a Lewis acid capable of accepting an electron pair. The solid acid may be an acid clay, a clay mineral such as kaolinite, a zeolite, a cation exchange resin such as Nafion (registered trademark), a metal oxide such as alumina, a metal salt such as magnesium sulfate, or a composite oxide such as silica-alumina. The action of the acid dissolves calcium contained in rocks in the ground or cement in structures as calcium ions. When calcium carbonate is precipitated as a sparingly soluble compound, the calcium ion concentration increases, allowing more calcium carbonate to be precipitated, thereby improving the efficiency of ground improvement. Furthermore, the action of the acid can dissolve carbonates with low solubility (such as magnesium carbonate) to increase the concentration of carbonate ions, allowing more calcium carbonate to precipitate and improving the efficiency of ground improvement.

[0052] The weight ratio of the ion supply material may be greater than the weight ratio of the acid. Alternatively, the ion supply material and the acid may be contained in the concretion accelerator in a separate state. This allows the ground to be efficiently concreted. Furthermore, when calcium carbonate is precipitated, the surrounding water environment is alkaline, which further enhances the efficiency of the precipitation. Therefore, the amount of acid generated and the rate of action that promotes concretion can be appropriately designed by the type and amount of acid added, depending on the surrounding water environment and the amount of carbonate ions to be precipitated.

[0053] The ion supplying material may further include a base material that coats the ions, the first compound, the second compound, the acid, or the like. The base material may be a material that has fluidity that allows it to be injected into voids in the ground, boreholes, or the like, and that hardens after injection through chemical reactions such as hydration or polymerization, or through heating, cooling, drying, light, or the like. The base material may be, for example, cement, mortar, concrete, or the like; a thermosetting resin such as epoxy resin; a thermoplastic resin such as polyethylene terephthalate or acrylic resin; a polymer compound such as starch or a water-absorbent polymer; or a mixture thereof. The ion supplying material in a solidified base material state may be inserted into the ground.

[0054] The ion supplying material may be encapsulated or coated in a microcapsule. The microcapsule may have any structure as long as it can hold or support the ion supplying material in a sustained release manner. For example, it is preferable that a part or all of the ion supplying material is covered with a film such as a coating agent, or is held or supported by a support. Furthermore, the material constituting the microcapsule may disintegrate when it comes into contact with water or moisture such as humidity. In this case, the timing and amount of release of cations or anions from the ion supplying material can be more effectively controlled.

[0055] The material constituting the microcapsules preferably contains a resin, which improves the dispersibility of the ion supplying material, allows for good control of the timing and amount of release of cations or anions, and enables the surface of the ion supplying material to be uniformly coated.

[0056] Examples of the resin include a water-soluble resin, a thermoplastic resin, a thermosetting resin, a photocurable resin, and a moisture-curable resin. Only one type of resin may be used, or two or more types may be used in combination.

[0057] Examples of the water-soluble resin include polyvinyl alcohol, polylactic acid resin (PLA resin), poly(meth)acrylic acid, poly(meth)acrylamide, polyvinylpyrrolidone, polyethylene oxide, and methyl cellulose.

[0058] Examples of thermoplastic resins include polyolefin resins, polyvinyl chloride resins, polyamide resins, polycarbonate resins, polystyrene resins, polyester resins, acrylonitrile-butadiene-styrene resins (ABS resins), polyethylene terephthalate (PET), and polymethyl methacrylate (PMMA).

[0059] Examples of polyolefin resins include polyethylene, polypropylene, polystyrene, polybutene, polyisobutylene, polybutadiene, ethylene-vinyl acetate copolymer, and ethylene-α-olefin copolymer.

[0060] Examples of the thermosetting resin include epoxy resin, phenol resin, (meth)acrylic resin, unsaturated polyester resin, vinyl ester resin, polyimide resin, urethane resin, polyurea resin, etc. The thermosetting resin may be used in combination with a thermosetting agent, a crosslinking agent, and a catalyst.

[0061] Examples of the photocurable resin include (meth)acrylic resin, (meth)acrylic urethane resin, epoxy resin, silicone resin, etc. The photocurable resin may be used in combination with a photopolymerization initiator.

[0062] Examples of the moisture-curable resin include moisture-curable urethane resins and hydrolyzable silyl group-containing resins.

[0063] From the viewpoint of better controlling the timing and amount of release of cations or anions from the ion supply material, the resin preferably contains a thermoplastic resin, more preferably contains a polyolefin resin, further preferably contains an ethylene-vinyl acetate copolymer, and particularly preferably is an ethylene-vinyl acetate copolymer.

[0064] The ion supply material may contain an additive. In particular, when the ion supply material contains a resin, the ion supply material may contain an additive for polymerizing or curing the resin, an additive for processing or shaping the ion supply material containing the resin, or an additive for improving the durability and weather resistance of the ion supply material containing the resin. Only one type of additive may be used, or two or more types may be used in any combination.

[0065] 2 shows examples of additives that can be added to the ion supply material. In the figure, double circles, circles, and triangles indicate combinations of the type of resin contained in the ion supply material and the additives that can be contained.

[0066] The additive may include a catalyst for polymerizing a thermoplastic resin such as polyethylene terephthalate (PET), polyethylene (PE), polypropylene (PP), or ethylene-vinyl acetate copolymer (EVA). The catalyst may include an organometallic compound. The organometallic compound may include a Ziegler-Natta catalyst, an organolead compound, or the like. The catalyst may include an emulsifier used in emulsion polymerization of the thermoplastic resin. The emulsifier may include a surfactant.

[0067] The additives may include a curing agent, a curing accelerator, and a crosslinking agent for curing curable resins such as epoxy resins and unsaturated polyesters. The curing agent may include a Sn-based curing agent for curing epoxy resins at room temperature, or benzoyl peroxide, which is used in radical polymerization. The curing accelerator may include imidazole, which is used in curing epoxy resins, or cobalt naphthenate, which is used in curing polyesters. The crosslinking agent may include a radical-based crosslinking agent such as divinylbenzene, styrene, or diallyl phthalate, or a functional group-based crosslinking agent such as a polyfunctional amine or a polyfunctional carboxylic acid.

[0068] The additives may include release agents, lubricants, plasticizers, thickeners, thixotropic agents, viscosity reducers, etc. for processing or molding ion supply materials containing resins. The release agents may include zinc stearate, fatty acids, etc. The lubricants may include PE wax, epoxidized soybean oil, calcium stearate, etc. The plasticizers may include phthalates such as diethyl phthalate, adipates, etc. The thickeners and thixotropic agents may include acrylic acid polymers, silica (inorganic powder) fine particles (Aerosil), magnesium oxide, etc. The viscosity reducers may include reactive diluents such as alkyl glycidyl ethers, compatible solvents such as xylene, and similar low molecular weight substances such as styrene monomers and ester oligomers.

[0069] The additives may include nucleating agents, impact modifiers, pigments, dyes, reinforcing agents, flame retardants, extenders, compatibilizers, surface treatment agents, etc., which are added when processing or molding ion supply materials containing resins. The nucleating agents may include talc, silica, graphite, magnesium oxide, calcium benzoate, etc. The impact modifiers may include acrylic rubber, butadiene rubber, etc. The pigments and dyes may include iron oxide, carbon black, titanium oxide, etc. The reinforcing agents and flame retardants may include glass fillers, aluminum hydroxide, magnesium hydroxide, ceramic particles (carbides, nitrides, oxides), etc. The extenders may include calcium carbonate, silica sand, clay, metal powders (tungsten, stainless steel, high-silicon cast iron), etc. The compatibilizers and surface treatment agents may include copolymerized oligomers, silane coupling agents, etc., which are added when mixing different materials such as organic and inorganic substances.

[0070] The additives may include antioxidants, ultraviolet absorbers, etc. The antioxidants may include alkylphenols, organic phosphites, etc. The ultraviolet absorbers may include benzotriazole, hindered diamine, etc.

[0071] The ion supply material may be colored according to the type or amount of ions to be supplied. For example, an ion supply material containing a first compound may be colored red, an ion supply material containing a second compound may be colored blue, and an ion supply material containing both the first compound and the second compound may be colored purple. This can prevent errors during application and distribution.

[0072] The ion supplying material may contain a hardly soluble material that serves as a crystal nucleus for promoting the precipitation of the hardly soluble compound. The hardly soluble material may be a compound that is hardly soluble in water, a metal such as iron, or a mineral such as sand or rock. The hardly soluble material may be the same as or different from the hardly soluble compound precipitated by the ions supplied from the ion supplying material. The hardly soluble material may be in the form of a powder.

[0073] The ion supplying material may be in a powder form. In this case, the ion supplying material may be mixed with an improving material such as cement and supplied to the ground.

[0074] The ion supplying material may be in a liquid or gel form, and in this case, the ion supplying material may be injected into the ground alone or together with an improvement material or the like.

[0075] The ion supply material may include an ion exchange resin to which ions forming a poorly soluble compound are adsorbed. In this case, the ion exchange resin can be selected or designed to release ions in an appropriate amount and at an appropriate supply rate depending on the type of ions to be supplied and the components, amounts, and pH of chemical substances dissolved in the groundwater surrounding the ion supply material.

[0076] The ion supply material may comprise a sheet containing ions that form a sparingly soluble compound. In this case, too, the material, thickness, shape, etc. of the sheet can be selected or designed so as to release ions in an appropriate amount and supply rate depending on the type of ions to be supplied and the components, amount, pH, etc. of chemical substances dissolved in the groundwater surrounding the ion supply material. When the ion supply material comprises a sheet, the sheet may be attached to the surface of a structural material or to the bedrock or stratum on which the structural material is disposed.

[0077] The ion supplying material may include a capsule containing ions that form a poorly soluble compound, a first compound, a second compound, an acid, etc. In this case, too, the material, thickness, shape, etc. of the capsule can be selected or designed so as to release ions in an appropriate amount and supply rate depending on the type of ions to be supplied and the components, amount, pH, etc. of the chemical substances dissolved in the groundwater surrounding the sealant.

[0078] Fig. 3 is a flowchart showing the procedure of the ground improvement method according to the first embodiment of the present disclosure. Fig. 3 shows details of step S16 in Fig. 1. Fig. 4 is a diagram for explaining the procedure of the ground improvement method shown in Fig. 3.

[0079] As shown in Fig. 4(a), a first ion supply material injection hole 2 is drilled in the ground 1 to inject a first ion supply material for supplying one of cations and anions (first ions) that form a poorly soluble compound (S20). As shown in Fig. 4(b), a first ion supply material 3 is injected into the drilled first ion supply material injection hole 2 (S22). A predetermined period of time is waited until the first ions are sufficiently diffused from the injected first ion supply material 3.

[0080] As shown in FIG. 4( c), after a predetermined period of time has elapsed and the first ions have diffused into the ground 1, second ion supply material injection holes 4 are drilled in the ground 1 to inject a second ion supply material for supplying the other of the cations and anions (second ions) that form the poorly soluble compound (S24). A plurality of second ion supply material injection holes 4 may be provided around the first ion supply material injection hole 2. The second ion supply material injection holes 4 may be provided in the region where the first ions supplied from the first ion supply material 3 have diffused. As shown in FIG. 4( d), a second ion supply material 5 is injected into the drilled second ion supply material injection hole 4 (S26). The second ions diffuse from the injected second ion supply material 5 and react with the first ions to precipitate a poorly soluble compound (S28). This allows the poorly soluble compound to precipitate over a wide area of ​​the ground 1, thereby blocking voids in the ground 1.

[0081] The diffusion coefficient of the first ion and the diffusion coefficient of the second ion may be different. In this case, even if the first ion supply material 3 and the second ion supply material 5 are supplied to the ground 1 simultaneously, the ions with faster diffusion will diffuse over a wider range first, followed by the ions with slower diffusion, which will react with the ions that diffused earlier to precipitate a poorly soluble compound. This also allows the poorly soluble compound to be precipitated over a wider range in the ground 1, thereby blocking voids in the ground 1. The diffusion coefficient of the first ion may be 1.2 times or more, 1.4 times or more, 1.6 times or more, 1.8 times or more, 2 times or more, 2.2 times or more, 2.4 times or more, 2.6 times or more, 2.8 times or more, or 3 times or more the diffusion coefficient of the second ion.

[0082] In ground where water is moving due to free water, etc., if the amount of water movement is small, the amount of ions that move with the water is also small. If the amount of water movement is large, the ions will be washed away with the water before reaching a supersaturated state, and poorly soluble compounds will not precipitate. If the amount of ion movement is greater than the hydraulic conductivity (diffusion coefficient) of the ground, many ions will be present in the water supply through which the ions move, reaching a supersaturated state and causing poorly soluble compounds to precipitate. Then, as the hydraulic conductivity decreases further, the ion supersaturation state will slowly spread, and the precipitation of poorly soluble compounds will spread throughout the ground, averaging out.

[0083] In stagnant ground with little water movement, diffusion due to ion concentration gradients becomes dominant. In this case, the ground is densified by precipitated calcium carbonate, using the same principle as the spherical lumps called concretions found in sedimentary rock layers, forming an extremely hard and strong ground.

[0084] If the magnitude relationship between the permeability coefficient Ka of the ion supply material or ion supply material injection hole, the permeability coefficient Kb of the ground in which the ion supply material is provided, and the permeability coefficient Kc of the excavated damaged zone (EDZ) of the ground is Kc > Ka > Kb or Ka > Kc > Kb, many ions supplied from the ion supply material are retained in the EDZ, which promotes densification of the EDZ and significantly improves the water-stopping properties of the EDZ. In particular, if Ka > Kc > Kb, the EDZ is more likely to be densified. Therefore, the permeability coefficient Ka of the ion supply material or ion supply material injection hole for improving the permeability coefficient of the EDZ is preferably greater than the permeability coefficient of the ground in which the ion supply material is provided. The permeability coefficient Ka of the ion supply material or ion supply material injection hole may be smaller than the permeability coefficient of the ground in which the ion supply material is provided. In this case, ions are slowly and gradually released, allowing the water-stopping effect to be maintained for a long period of time.

[0085] The step of obtaining an index representing the permeability of the ground (S10) may be omitted. In this case, the ground improvement method of the present disclosure comprises the steps of reducing the permeability of the ground and supplying an ion supply material to the ground to supply ions capable of forming a poorly soluble compound. These steps may be performed simultaneously or in any order.

[0086] The method for improving ground according to the present disclosure may include the steps of supplying, to the ground, an ion supplying material that slowly releases ions capable of forming a poorly soluble compound, and supplying, to the ground, an acid that donates protons. These steps may be performed simultaneously or in any order.

[0087] [Example] A permeability test was conducted on a test specimen improved using the method according to the first embodiment. When water flows through soil in a laminar manner, a proportional relationship exists between the hydraulic gradient and the flow velocity through the soil. The proportionality coefficient (m / sec) is the permeability coefficient. Laboratory permeability tests are performed using either the constant water level method or the variable water level method. The constant water level method is generally applied to samples with relatively high permeability, while the variable water level method is applied to samples with relatively low permeability. In the constant water level method, a constant water level difference h is applied to the test specimen, the permeability per unit time Q is measured, and the permeability coefficient k is calculated using Darcy's equation. In the variable water level method, the water level difference h from the water surface in a thin standpipe is changed, and the time it takes for the water level difference to change from h1 to h2 is measured. The permeability coefficient k is calculated using a formula. Permeability tests were conducted immediately after water flow began, one week later, and six months later to calculate the permeability coefficient.

[0088] [Example 1] Approximately 30 kg of Toyoura standard sandy ground specimens were used as test specimens, 5 kg of cement-based solidification material (ordinary Portland cement powder) was used as improvement material, and 5 kg of ion supply materials were used: particles of calcium acetate coated with polyethylene terephthalate (PET) resin obtained by melt-mixing calcium acetate and PET resin at a weight ratio of 1:1, and 5 kg of particles of sodium carbonate coated with PET resin obtained by melt-mixing sodium carbonate and PET resin at a weight ratio of 1:1. These were mixed in a mixer, and then the mixture was filled into a container and water was allowed to flow through. The hydraulic conductivity was measured using the constant water level method immediately after the water had been passed through, and after one week and six months.

[0089] [Example 2] A core of tuff breccia with an outer diameter of 10 cm was cut into a piece of tuff breccia with a height of 12 cm, and the piece was placed in a cylindrical container whose inner surface was coated with bentonite. The hydraulic conductivity was measured, and the value was 4 × 10 －５ It was confirmed that the permeability was m / s. An improvement material liquid injection hole with an outer diameter of 1 cm and a depth of 5 cm was made on the surface of the test specimen, and the improvement material was an epoxy resin that solidifies by mixing two liquids, a main material and a hardener, and an ion supply material made by mixing calcium chloride and sodium carbonate powders at 75 parts by weight of each resin. Water was continued to flow, and the hydraulic conductivity was measured after 1 week and 6 months using the changing water level method.

[0090] [Example 3] As a test specimen, an excavated silt clay layer was filled into a cylindrical container with an inner diameter of 10 cm to a height of 12 cm. The hydraulic conductivity was measured and the value was 7 × 10 －７ It was confirmed that the permeability was m / s. The specimen was the same silt clay layer, and two ion supply materials, calcium formate granulated after melt-mixing with PET resin and sodium carbonate granulated after melt-mixing with PET resin, were mixed in a mixer at a weight fraction of 30% each relative to the silt clay material. The mixture was then filled to a height of 12 cm in a cylindrical can with an inner diameter of 10 cm while vibrating. Water was allowed to flow through the can, and the hydraulic conductivity was measured after one week and six months using the head method.

[0091] [Example 4] As a test specimen, approximately 30 kg of Toyoura standard sandy ground specimen was used, and as an improvement material and first ion supply material, 1 kg of pellets obtained by melt-mixing 5 kg of cement-based solidification material (ordinary Portland cement powder), anhydrous citric acid, and low-melting-point PET resin, and 2 kg of particles of sodium carbonate coated with PET resin obtained by melt-mixing sodium carbonate and PET resin in a weight ratio of 1:1 were mixed in a mixer, and then the mixture was filled into a container and water was started to flow through. The hydraulic conductivity was measured using the constant water level method immediately after the water flow, after one week, and after six months.

[0092] [Example 5] Approximately 30 kg of Toyoura standard sandy ground specimens were filled into a container, and ordinary Portland cement (a 2:1 mixture of water and cement) was infiltrated from the top as an improvement agent. Water flow was continued, and after two weeks, a 20 mm diameter, 10 cm deep injection hole was drilled in the center, and a suspension of sodium bicarbonate and epoxy resin was injected as the first ion supply material. Three months later, a 10 mm diameter, 20 cm deep injection hole was drilled 5 cm away from the central injection hole, and a suspension of calcium formate and epoxy resin was injected as the second ion supply material. The hydraulic conductivity was measured one week and six months later using the constant water level method.

[0093] [Comparative Example 1] As a test specimen, approximately 30 kg of Toyoura standard sandy ground specimen and 5 kg of cement-based solidification material (ordinary Portland cement) as an improvement material were mixed in a mixer, then filled into a container and water was started to flow through. The hydraulic conductivity was measured immediately after water flow, one week later, and six months later using the constant water level method. In other words, in Comparative Example 1, no ion supply material was added to the test specimen.

[0094] [Comparative Example 2] Approximately 30 kg of Toyoura standard sandy ground specimen was mixed with 5 kg of ion supplying materials, namely, particles coated with calcium acetate by PET resin obtained by melt-mixing calcium acetate and PET resin at a weight ratio of 1:1, and particles coated with sodium carbonate by PET resin obtained by melt-mixing sodium carbonate and PET resin at a weight ratio of 1:1, in a mixer. The mixture was then filled into a container, and water was started to flow through. The hydraulic conductivity was measured by the constant water level method immediately after water flow, one week later, and six months later. That is, in Comparative Example 2, an ion supplying material was added to the specimen, but the hydraulic conductivity of the specimen was 3 x 10 －２ m / s, but the ion supply material was added without improving the permeability with an improvement material.

[0095] Figure 5 shows the results of the permeability test. In Examples 1 to 5 and Comparative Example 1, the improvement material solidified after one week, improving the permeability, and the permeability coefficient reached 10 －６ ~10 －７ In Comparative Example 2, since no improvement material was added, the permeability coefficient after one week was 3 × 10 －２ m / sec.

[0096] In Examples 1 to 5, the effect of the ion supply material was further manifested after 6 months, and the water permeability coefficient was 10 －８ ~10 －１０ The permeability coefficient has decreased to about 10 －７ If the thickness is less than this, it can be said that the specimen is substantially impermeable. In Examples 1 to 5, the water-stopping properties of the specimens were improved to the point where they were substantially impermeable.

[0097] In Comparative Example 1, since no ion supplying material was added, the water permeability coefficient after 6 months was 1 × 10 －６In Comparative Example 2, an ion supplying material was added, but the water permeability coefficient after 6 months was 2 × 10, which was almost the same as that immediately after water flow. －２ In Comparative Example 2, the ion supply material was added to the test specimen while the water permeability was still high, so it is thought that calcium ions and carbonate ions were washed away before calcium carbonate precipitated.

[0098] In Example 4, a lower hydraulic conductivity was measured than in Examples 1 to 3. In Example 4, the improvement material contained cement and citric acid, so calcium ions were supplied from the cement neutralized by citric acid, and it also functioned as a first ion supply material. This is thought to have led to the efficient precipitation of calcium carbonate.

[0099] In Example 5, a lower hydraulic conductivity was measured than in Examples 1 to 4. In Example 5, it is believed that calcium carbonate precipitated more efficiently because bicarbonate ions or carbonate ions penetrated throughout the interior of the specimen and calcium ions were supplied only after a sufficient concentration was reached.

[0100] [Example 6] An experiment was conducted to evaluate the sustained release of ions and acids contained in the ion supply material. Approximately 3.3 L (approximately 4 kg) of the ion supply material, which contained 70 parts by weight of an ion-containing compound and 100 parts by weight of a liquid resin as a base material, was injected into a borehole with a diameter of 50 mm and a depth of 1.5 m and allowed to harden. After two years, the hardened body was removed and the distribution of calcium ions was measured. It was confirmed that approximately 30% of the calcium ions had been released from the ion supply material.

[0101] A small test piece of 20 mm diameter and 10 mm height was molded from an ion supply material containing 50 parts by weight of sodium bicarbonate and 100 parts by weight of liquid resin, and immersed in 300 cc of water. It was confirmed that approximately 50% of the ions were released from the ion supply material in six months.

[0102] A sample of an ion supply material containing 25 parts by weight of sodium carbonate, 25 parts by weight of calcium formate, and 100 parts by weight of liquid resin was molded into a rectangular column and immersed in 300 cc of water. It was confirmed that approximately 30% of the sodium ions were released in half a month.

[0103] A few grams of powder made by melt-mixing 20 parts by weight of solid acid (anhydrous citric acid) and 100 parts by weight of low-melting-point PET was immersed in 300 cc of water. It was confirmed that more than 90% of the acid had dissolved and protons had been released within two weeks.

[0104] In this way, it was confirmed that the ion supply material of this embodiment gradually releases ions and protons.

[0105] (Sealant) The technology of the present disclosure described above can also be applied to a sealant for sealing the ground, structures, etc. The sealant according to the present disclosure includes a resin and an ion-releasing compound capable of releasing cations or anions (hereinafter, may be referred to as "ion-releasing compound"). In the sealant according to the present disclosure, the ion-releasing compound is capable of generating a poorly water-soluble salt. In the sealant according to the present disclosure, the poorly water-soluble salt has a specific gravity of 2.0 or more and a solubility in water of 1.0 x 10 at 20°C. －３ The sealant according to the present disclosure is a sealant for producing a poorly water-soluble salt.

[0106] The sealant according to the present disclosure has the above-described configuration, thereby improving the waterproofing of the sealed area and its surroundings and maintaining the structure in a stable state for a long period of time. More specifically, when the sealant is placed in the sealed area of ​​the object to be sealed, the ion-releasing compound in the sealant releases ions, generating poorly water-soluble salts and forming concretions. This densifies the sealed area and its surroundings, effectively preventing water leakage (improving waterproofing), and maintaining the structure in a stable state for a long period of time (improving durability). The technology of the present disclosure contributes to the preventive maintenance of structures. The technology of the present disclosure contributes to the preventive maintenance of both newly constructed and existing structures.

[0107] The sealant according to the present disclosure may further contain a proton-donating acid. This can promote concretion of the sealant, thereby enhancing the sealing effect of the sealant. The ion-releasing compound of the sealant according to the present disclosure may be the same as the compound contained in the ion supply material of the above-mentioned concretion-promoting material.

[0108] In the sealant according to the present disclosure, when the sealant comes into contact with moisture or the like adhering to the ground or a structure at a sealed location, the ion-releasing compound in the sealant releases ions, thereby generating a poorly water-soluble salt at the contact surface between the sealant and the moisture or the like. That is, the sealant according to the present disclosure can generate a layer of poorly water-soluble salt on the surface of the sealant. The generated poorly water-soluble salt further increases the strength of the sealed location and its surroundings. The generated poorly water-soluble salt is generally thought to be generated over several months to several years. The generated poorly water-soluble salt effectively prevents further contact between the sealant and moisture, thereby effectively preventing deterioration of the sealant and the structure. In addition, when the resin in the sealant contains a curable resin, the generated poorly water-soluble salt can effectively prevent deterioration of the sealant after the curing reaction of the curable resin, thereby effectively preventing deterioration of the cured product (sealed product) of the sealant. Furthermore, when the resin in the sealing material contains a thermoplastic resin, the generated poorly water-soluble salt can effectively suppress deterioration of the sealing material after molding, and can effectively suppress deterioration of the molded body of the sealing material (sealed product).

[0109] In the sealant, the poorly water-soluble salt may have a specific gravity of 2.0 or more. From the viewpoint of further improving durability against external stress, the specific gravity of the poorly water-soluble salt is preferably 2.1 or more, more preferably 2.2 or more, even more preferably 2.5 or more, and is preferably 5.0 or less, more preferably 4.5 or less, even more preferably 3.5 or less.

[0110] The specific gravity of the poorly water-soluble salt can be measured by the liquid immersion method using an electronic balance precision specific gravity meter, such as the "Electronic Specific Gravimeter EDM2103" manufactured by AS ONE Corporation.

[0111] In the sealing material, the solubility of the poorly water-soluble salt in water at 20°C is 1.0 x 10 －３ From the viewpoint of further enhancing the waterproofing of the sealed area and its surroundings, the solubility of the poorly water-soluble salt in water at 20°C is preferably 8.0 × 10 mol / L or less. －４ mol / L or less, more preferably 5.0 × 10 －４ mol / L or less, more preferably 2.0 × 10 －４ The lower limit of the solubility of the poorly water-soluble salt in water at 20°C is not particularly limited. The solubility of the poorly water-soluble salt in water at 20°C is 1.0 × 10 －１０ mol / L or more, and may be 1.0 x 10 －９ mol / L or more.

[0112] The solubility of the above-mentioned poorly water-soluble salt in water at 20°C can be measured by the following method. 10 g of the poorly water-soluble salt is added to 100 g of pure water, and the mixture is stirred at 20°C for 10 minutes. Then, 10 g of the solution is placed in an evaporating dish, and the water is completely removed at 100°C. The solubility of the above-mentioned poorly water-soluble salt in water at 20°C is calculated from the weight of the poorly water-soluble salt remaining on the evaporating dish.

[0113] The viscosity (η23) of the sealant at 23°C is preferably 500 mPa·s or more, more preferably 10,000 mPa·s or more, and preferably 2,000,000 mPa·s or less, more preferably 1,000,000 mPa·s or less. When the viscosity (η23) is equal to or greater than the lower limit and equal to or less than the upper limit, the sealant can be easily filled (injected), improving workability. The viscosity (η23) can be adjusted appropriately by changing the types and amounts of the components used.

[0114] The viscosity (η23) can be measured, for example, using a Brookfield viscometer (VISCOSTAR manufactured by FUNGILAB) under conditions of 23° C. and 20 rpm.

[0115] Furthermore, the sealant according to the present disclosure can be used whether the area to be sealed is dry or wet. Furthermore, the sealant according to the present disclosure can be used even when water is leaking from the area to be sealed. Therefore, the sealant according to the present disclosure can preserve structures for various applications.

[0116] The structure is not particularly limited. Examples of the structure include concrete structures. Examples of the concrete structure include insulators (grout portions) arranged on the outer surfaces of buildings, underground tunnels, undersea tunnels, mountain tunnels, and pipes. From the viewpoint of more effectively exerting the effects of the present disclosure, the structure is preferably a concrete structure. The structure may also be an underground structure.

[0117] The sealant according to the present disclosure is preferably used for gaps (gaps) in structures. The sealant according to the present disclosure is preferably used for cracks or fissures in structures. The sealant according to the present disclosure is preferably used for gaps (joints) at joints between members in structures. Furthermore, the sealant according to the present disclosure is preferably used at the boundary between a structure and the ground behind the structure. Furthermore, the sealant according to the present disclosure is preferably used for sheathing materials. Specifically, the sealant according to the present disclosure is preferably used for sheathing materials for insulators (grout portions) arranged on the outer surfaces of anchors, cables, pipes, etc. The sealant according to the present disclosure is preferably used to protect the outer surfaces of insulators arranged on the outer surfaces of anchors, cables, pipes, etc.

[0118] Furthermore, at final waste disposal sites, waterproof sheets are sometimes installed at the boundary between concrete structures and the ground. Furthermore, in the NATM method, which is one of the tunnel excavation methods, a waterproof sheet is sometimes installed at the boundary between the tunnel (lining concrete) and the ground behind the tunnel. The sealant according to the present disclosure is suitable for use as a material for the waterproof sheet.

[0119] From the viewpoint of more effectively achieving the effects of the present disclosure, it is preferable that the sealant is a sealant for an object to be sealed, including concrete. From the viewpoint of more effectively achieving the effects of the present disclosure, it is preferable that the sealant is a sealant for a concrete structure. From the viewpoint of more effectively achieving the effects of the present disclosure, it is preferable that the sealant is placed in a portion to be sealed of an object to be sealed, including concrete. The sealant may be a sealant for an object to be sealed, including ground and concrete. The sealant may be placed in a portion to be sealed of an object to be sealed, including ground and concrete.

[0120] The following describes in detail each component used in the sealant according to the present disclosure.

[0121] <Resin> The sealing material contains a resin.

[0122] Examples of the resin include thermoplastic resins and curable resins. From the viewpoint of easily molding the sealant by extrusion molding or injection molding, the resin preferably includes a thermoplastic resin. From the viewpoint of effectively sealing the target part by injecting or applying the sealant, the resin preferably includes a curable resin. Only one type of the resin may be used, or two or more types may be used in combination.

[0123] Examples of the thermoplastic resin include fluororesin, polyolefin resin, polyvinyl chloride resin, polyamide resin, polycarbonate resin, polystyrene resin, polyester resin, acrylonitrile-butadiene-styrene resin (ABS resin), polyethylene terephthalate (PET), and polymethyl methacrylate (PMMA).

[0124] Examples of the polyolefin resin include polyethylene, polypropylene, ethylene-propylene copolymer (EPDM), isobutylene-isoprene copolymer, polystyrene, polybutene, polyisobutylene, polybutadiene, acrylonitrile-butadiene copolymer, ethylene-vinyl acetate copolymer, and ethylene-α-olefin copolymer.

[0125] Examples of the curable resin include modified silicone resin, silicone resin, epoxy resin, acrylic resin, unsaturated polyester resin, polyurea resin, urethane resin, phenol resin, vinyl ester resin, naphthoxazine resin, etc. The curable resin may be used alone or in combination of two or more.

[0126] The curable resin may be a one-component curable resin or a two-component curable resin. Examples of the one-component curable resin include a thermosetting resin, a photocurable resin, and a moisture-curable resin. The two-component curable resin is used in combination with a curing agent. From the viewpoint of improving workability on site, the curable resin preferably contains a moisture-curable resin, and is preferably a moisture-curable resin. The curable resin may be used in combination with a curing agent, or may not be used in combination with a curing agent.

[0127] From the viewpoint of increasing elasticity, the curable resin preferably contains a modified silicone resin, and is preferably a modified silicone resin.

[0128] From the viewpoint of improving workability on site, the modified silicone resin is preferably a moisture-curable modified silicone resin. The moisture-curable modified silicone resin has a hydrolyzable silicon group. The modified silicone resin having a hydrolyzable silicon group has a polyether polymer, a polyolefin polymer, or an acrylic polymer as the main chain (the portion excluding the hydrolyzable silicon group). Therefore, examples of monomers that serve as the main chain include alkylene oxide monomers, olefin monomers, and acrylic monomers. The polymer may be a homopolymer or a copolymer. When the polymer is a copolymer, examples of the monomers used include alkylene oxide monomers, olefin monomer components, acrylic monomers, and vinyl monomers. Only one type of modified silicone resin may be used, or two or more types may be used in combination.

[0129] Examples of the alkylene oxide monomer include ethylene oxide, propylene oxide, butylene oxide, etc. From the viewpoint of improving the elongation and viscous handleability after curing, the alkylene oxide monomer is preferably polypropylene oxide obtained by polymerizing propylene oxide.

[0130] Examples of the olefin-based monomer include isobutylene.

[0131] Examples of the acrylic monomer include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, n-butyl (meth)acrylate, tert-butyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, isononyl (meth)acrylate, isomyristyl (meth)acrylate, stearyl (meth)acrylate, and isobornyl (meth)acrylate. acrylate, benzyl (meth)acrylate, 2-butoxyethyl (meth)acrylate, 2-phenoxyethyl (meth)acrylate, glycidyl (meth)acrylate, tetrahydrofurfuryl (meth)acrylate, hexanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, polyethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, Dimethylolpropane tri(meth)acrylate, pentaerythritol di(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol hexa(meth)acrylate, epoxy acrylate, polyester acrylate, urethane acrylate, 2-hydroxyethyl(meth)acrylate, 3-hydroxypropyl(meth)acrylate, 2-hydroxypropyl(meth)acrylate, 4-hydroxybutyl(meth)acrylate ) acrylate, 2-hydroxybutyl (meth)acrylate, 5-hydroxypentyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 3-hydroxy-3-methylbutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (meth)acrylate, pentaerythritol tri(meth)acrylate, 2-[(meth)acryloyloxy]ethyl 2-hydroxyethyl phthalate, 2-[(meth)acryloyloxy]ethyl 2-hydroxypropyl phthalate, and the like.When the acrylic polymer is one in which other vinyl monomer components have been copolymerized, a hydrolyzable silicon group can be introduced by copolymerizing a vinyl monomer component having a hydrolyzable silicon group.

[0132] From the viewpoint of improving weather resistance, the main chain of the modified silicone resin preferably has a structural unit derived from an acrylic monomer.

[0133] From the viewpoint of improving weather resistance, the content of structural units derived from acrylic monomers in 100% by weight of the main chain in the modified silicone resin is preferably 5% by weight or more, and preferably 20% by weight or less.

[0134] The hydrolyzable silicon group is not particularly limited, but examples thereof include halogenated silyl groups, alkenyloxysilyl groups, acyloxysilyl groups, aminosilyl groups, aminooxysilyl groups, oximesilyl groups, amidosilyl groups, and alkoxysilyl groups.

[0135] The number of hydrolyzable groups bonded to a silicon atom in the hydrolyzable silicon group is preferably 1 or more, and preferably 3 or less. The number of hydrolyzable groups bonded to one silicon atom may be one type, or two or more types. The hydrolyzable group and a non-hydrolyzable group may be bonded to one silicon atom. Due to their excellent stability and ease of handling, the hydrolyzable silicon group is preferably a monoalkoxysilyl group, a dialkoxysilyl group, or a trialkoxysilyl group.

[0136] When the curable resin contains the modified silicone resin, the curable resin preferably contains a silanol condensation catalyst. The curable resin preferably contains the modified silicone resin and a silanol condensation catalyst. By using the silanol condensation catalyst, the modified silicone resin can be cured in a short time. The silanol condensation catalyst may be used alone or in combination of two or more.

[0137] Examples of the silanol condensation catalyst include tin catalysts such as monoalkyltin esters and dialkyltin esters, poly(dialkylstannoxane) disilicate resins, and organic titanates.

[0138] Examples of the monoalkyltin esters include butyltin tris(2-ethylhexanoate), etc. Examples of the dialkyltin esters include dibutyltin acetate, dibutyltin dilaurate, dibutyltin dioctoate, dibutyltin dioleate, dibutyltin dimethoxide, dibutyltin diphenoxide, dibutyltin diacetylacetonate, dibutyltin acetoacetate, and stannous octoate.

[0139] Examples of the organic titanate include titanium alkoxides such as tetrabutyl titanate, tetraisopropyl titanate, tetramethyl titanate, and tetra(2-ethylhexyl titanate)triethanolamine titanate; and titanium chelates such as titanium tetraacetylacetonate, titanium ethylacetoacetate, and octylene glycolate.

[0140] The content of the silicone condensation catalyst is preferably 0.1 parts by weight or more, more preferably 1 part by weight or more, preferably 10 parts by weight or less, more preferably 5 parts by weight or less, relative to 100 parts by weight of the modified silicone resin.When the content of the silicone condensation catalyst is above the lower limit, the material of the resin layer containing the modified silicone resin can be cured in a short time, and the resin layer can be obtained well in a short time.When the content of the silicone condensation catalyst is below the upper limit, the adhesive strength of the resin layer can be increased.

[0141] Examples of the silicone resin include organopolysiloxanes having two or more alkenyl groups bonded to silicon atoms. The main chain of the organopolysiloxane is generally a diorganosiloxane polymer, but it may have a partially branched or cyclic structure. Examples of the alkenyl group contained in the organopolysiloxane include vinyl, 1-propenyl, 2-propenyl, isopropenyl, butenyl, 1-methyl-2-propenyl, petenyl, hexenyl, octenyl, and cyclohexenyl groups.

[0142] Examples of the curing agent (crosslinking agent) for the silicone resin include organohydrogenpolysiloxanes having two or more SiH groups. Examples of the organohydrogenpolysiloxane include phenylmethylhydrogenpolysiloxane, 1,1,3,3-tetramethyldisiloxane, 1,3,5,7-tetramethylcyclotetrasiloxane, methylhydrogenpolysiloxane blocked at both ends with trimethylsiloxy groups, dimethylsiloxane-methylhydrogensiloxane copolymer blocked at both ends with trimethylsiloxy groups, dimethylpolysiloxane blocked at both ends with dimethylhydrogensiloxy groups, dimethylsiloxane-methylhydrogensiloxane copolymer blocked at both ends with dimethylhydrogensiloxy groups, methylhydrogensiloxane-diphenylsiloxane copolymer blocked at both ends with trimethylsiloxy groups, and methylhydrogensiloxane-diphenylsiloxane-dimethylsiloxane copolymer blocked at both ends with trimethylsiloxy groups.

[0143] Examples of the epoxy resin include bisphenol-type epoxy resins such as bisphenol A-type epoxy resins, bisphenol F-type epoxy resins, bisphenol S-type epoxy resins, and hydrogenated versions thereof; glycidyl ether-type epoxy resins such as polypropylene glycol diglycidyl ether-type epoxy resins; ester-type epoxy resins such as phthalic acid diglycidyl ester-type epoxy resins; novolac-type epoxy resins such as phenol novolac-type epoxy resins, bisphenol A novolac-type epoxy resins, cresol novolac-type epoxy resins, and hydrogenated versions thereof; trisphenol-type polyfunctional epoxy resins such as triphenolmethane-type epoxy resins; triglycidyl isopropyl Examples of suitable epoxy resins include nitrogen-containing ring-type polyfunctional epoxy resins such as cyanurate-type epoxy resins, tetraglycidyldiaminodiphenylmethane-type epoxy resins, tetraglycidylmeta-xylenediamine-type epoxy resins, and hydantoin-type epoxy resins; condensed-ring epoxy resins such as naphthalene-type epoxy resins; biphenyl-type epoxy resins; dicyclopentadiene-type epoxy resins; ether ester-type epoxy resins; epoxy resins having an alicyclic structure such as 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate; urethane-type epoxy resins; and rubber-modified epoxy resins having a rubber skeleton such as polybutadiene and acrylonitrile butadiene rubber (NBR).

[0144] When the curable resin contains the epoxy resin, the curable resin preferably contains a curing agent for the epoxy resin (epoxy curing agent). That is, the curable component preferably contains the epoxy resin and the epoxy curing agent.

[0145] Examples of the epoxy resin curing agent (epoxy curing agent) include amine compounds, imidazole compounds, amide compounds, and cyano compounds. Examples of the amine compounds include ethylenediamine, propylenediamine, diethylenetriamine, triethylenetetramine, amine adducts thereof, metaphenylenediamine, diaminodiphenylmethane, and diaminodiphenylsulfone. Examples of the imidazole compounds include methylimidazole, 2-ethyl-4-methylimidazole, 1-isobutyl-2-methylimidazole, 1-benzyl-2-methylimidazole, 2-ethyl-4-methylimidazole, ethylimidazole, isopropylimidazole, 2,4-dimethylimidazole, phenylimidazole, undecylimidazole, heptadecylimidazole, 2-phenyl-4-methylimidazole, 2-phenyl-4,5-dihydroxymethylimidazole, and 2-phenyl-4-methyl-5-hydroxymethylimidazole. Examples of the amide compounds include polyamides, etc. Examples of the cyano compounds include dicyandiamide, etc.

[0146] The epoxy resin may be a latent curing agent such as ketimine, in which the active amine is blocked and which becomes active under certain conditions such as moisture. For example, ketimine is stable in the absence of moisture, but generally becomes a primary amine in the presence of moisture and reacts with the epoxy resin. Specific examples include 2,5,8-triaza-1,8-nonadiene, 2,10-dimethyl-3,6,9-triaza-2,9-undecadiene, 2,10-diphenyl-3,6,9-triaza-2,9-undecadiene, 3,11-dimethyl-4,7,10-triaza-3,10-tridecadiene, 3,11-diethyl-4,7,10-triaza-3,10-tridecadiene, 2,4,12,14-tetramethyl-5,8,11-triaza-4,11-pentadecadiene, 2,4,20,22-tetramethyl-5,12,19-triaza-4,19-trieicosadiene, and 2,4,15,17-tetramethyl-5,8,11,14-tetraaza-4,14-octadecadiene.

[0147] A cured product of the epoxy resin can be obtained by reacting the epoxy resin with the epoxy curing agent.

[0148] From the viewpoint of more effectively exerting the effects of the present disclosure, the epoxy resin preferably includes an epoxy resin having an aromatic skeleton, and is more preferably a bisphenol A type epoxy resin or a bisphenol F type epoxy resin.

[0149] From the viewpoint of more effectively exerting the effects of the present disclosure, the epoxy curing agent is preferably an amine-based curing agent (amine compound).

[0150] A urethane resin can be obtained by subjecting a polyol compound and an isocyanate compound to a curing reaction. Examples of the polyol compound include bisphenol A, bisphenol F, phenol novolac, cresol novolac, cyclohexanediol, methylcyclohexanediol, isophoronediol, dicyclohexylmethanediol, dimethyldicyclohexylmethanediol, ethylene glycol, propylene glycol, butanediol, pentanediol, hexanediol, polyester polyol, polyether polyol, a polymer obtained by dehydration condensation of a polybasic acid and a polyhydric alcohol, and a polymer obtained by ring-opening polymerization of a lactone such as ε-caprolactone or α-methyl-ε-caprolactone.

[0151] The isocyanate compound may be a polyisocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates, alicyclic polyisocyanates, and aliphatic polyisocyanates. Examples of the aromatic polyisocyanates include phenylene diisocyanate, toluene diisocyanate, tolylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, dimethyldiphenylmethane diisocyanate, triphenylmethane triisocyanate, naphthalene diisocyanate, and polymethylene polyphenyl polyisocyanate. Examples of the alicyclic polyisocyanates include cyclohexylene diisocyanate, methylcyclohexylene diisocyanate, isophorone diisocyanate, dicyclohexylmethane diisocyanate, and dimethyldicyclohexylmethane diisocyanate. Examples of the aliphatic polyisocyanate include methylene diisocyanate, ethylene diisocyanate, propylene diisocyanate, tetramethylene diisocyanate, and hexamethylene diisocyanate.

[0152] From the viewpoint of more effectively exhibiting the effects of the present disclosure, the polyol compound is preferably a polyester polyol or a polyether polyol, and the curing agent (isocyanate compound) for the polyol compound is preferably diphenylmethane diisocyanate or toluene diisocyanate.

[0153] The compounding ratio of the polyol compound to the polyisocyanate compound can be appropriately changed depending on the combination of the types of polyol compound and polyisocyanate compound. The compounding amount of the polyisocyanate compound is preferably an amount such that the amount of hydroxyl groups in the polyol compound is equal to the amount of isocyanate groups (NCO amount) in the polyisocyanate compound.

[0154] Examples of the phenol resin include novolac type phenol, biphenol type phenol, naphthalene type phenol, dicyclopentadiene type phenol, aralkyl type phenol, and dicyclopentadiene type phenol.

[0155] Examples of the curing agent for the phenolic resin include hexamethylenetetramine and paraformaldehyde.

[0156] Examples of the vinyl ester resin include a reaction product of an epoxy resin with an unsaturated monobasic acid. Examples of the epoxy resin include aliphatic glycidyl ethers such as bisphenol A diglycidyl ether and its high molecular weight homologues, novolac polyglycidyl ether and its high molecular weight homologues, and 1,6-hexanediol diglycidyl ether. Examples of the unsaturated monobasic acid include acrylic acid and methacrylic acid. Examples of the reaction product of the epoxy resin with the acrylic acid and methacrylic acid include epoxy (meth)acrylate.

[0157] Examples of the curing agent for the vinyl ester resin include organic peroxides, such as ketone peroxides, perbenzoates, hydroperoxides, diacyl peroxides, peroxyketals, hydroperoxides, diallyl peroxides, peroxyesters, and peroxydicarbonates.

[0158] When the curable resin contains the vinyl ester resin, the curable component may contain a radically polymerizable unsaturated monomer. Examples of the radically polymerizable unsaturated monomer include styrene monomers, α-, o-, m-, p-alkyl, nitro, cyano, amide, and ester derivatives of styrene, chlorostyrene, vinyltoluene, and divinylbenzene, and other styrene-based monomers, butadiene, 2,3-dimethylbutadiene, isoprene, and chloroprene, and other dienes; ethyl (meth)acrylate, methyl (meth)acrylate, n-propyl (meth)acrylate, i-propyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, dodecyl (meth)acrylate, and (meth)acrylate. (meth)acrylic acid esters such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, tetrahydrofuryl (meth)acrylate, acetoacetoxyethyl (meth)acrylate, dicyclopentenyloxyethyl (meth)acrylate, and phenoxyethyl (meth)acrylate; (meth)acrylic acid amides such as (meth)acrylic acid amide and (meth)acrylic acid N,N-dimethylamide; vinyl resins such as (meth)acrylic acid anilide; unsaturated dicarboxylic acid diesters such as diethyl citraconic acid; monomaleimide resins such as N-phenylmaleimide; and N-(meth)acryloylphthalimide.

[0159] The content of the resin in 100% by weight of the sealant is preferably 30% by weight or more, more preferably 50% by weight or more, even more preferably 55% by weight or more, particularly preferably 60% by weight or more, and preferably 97% by weight or less, more preferably 95% by weight or less, even more preferably 90% by weight or less, particularly preferably 80% by weight or less. When the content of the resin is above the lower limit and below the upper limit, cations or anions are released more effectively, and poorly water-soluble salts are produced well. As a result, the sealed area and its surroundings are further densified, allowing the structure to be maintained in a stable state for a longer period of time.

[0160] The content of the thermoplastic resin in 100% by weight of the sealant is preferably 40% by weight or more, more preferably 50% by weight or more, even more preferably 60% by weight or more, particularly preferably 65% ​​by weight or more, and preferably 97% by weight or less, more preferably 95% by weight or less, even more preferably 90% by weight or less, particularly preferably 85% by weight or less. When the content of the thermoplastic resin is above the above lower limit and below the above upper limit, cations or anions are released more effectively, and poorly water-soluble salts are produced well. As a result, the sealed area and its surroundings are further densified, and the structure can be maintained in a stable state for a longer period of time.

[0161] The content of the curable resin in 100% by weight of the sealant is preferably 30% by weight or more, more preferably 50% by weight or more, even more preferably 55% by weight or more, particularly preferably 60% by weight or more, and preferably 97% by weight or less, more preferably 95% by weight or less, even more preferably 90% by weight or less, particularly preferably 80% by weight or less. When the content of the curable resin is above the lower limit and below the upper limit, cations or anions are released more effectively, and poorly water-soluble salts are produced well. As a result, the sealed area and its surroundings are further densified, and the structure can be maintained in a stable state for a longer period of time.

[0162] The content of the moisture-curing resin in 100% by weight of the sealant is preferably 35% by weight or more, more preferably 50% by weight or more, even more preferably 55% by weight or more, particularly preferably 60% by weight or more, and preferably 95% by weight or less, more preferably 90% by weight or less, even more preferably 85% by weight or less, particularly preferably 80% by weight or less. When the content of the moisture-curing resin is above the lower limit and below the upper limit, cations or anions are released more effectively, and poorly water-soluble salts are produced well. As a result, the sealed area and its surroundings are further densified, and the structure can be maintained in a stable state for a longer period of time.

[0163] The content of the modified silicone resin in 100% by weight of the sealant is preferably 35% by weight or more, more preferably 50% by weight or more, even more preferably 55% by weight or more, particularly preferably 60% by weight or more, and is preferably 97% by weight or less, more preferably 95% by weight or less, even more preferably 90% by weight or less, particularly preferably 80% by weight or less. When the content of the modified silicone resin is above the above lower limit and below the above upper limit, cations or anions are released more effectively, and poorly water-soluble salts are produced well. As a result, the sealed area and its surroundings are further densified, and the structure can be maintained in a stable state for a longer period of time.

[0164] <Ion-Releasing Compound> The sealant contains an ion-releasing compound capable of releasing cations or anions (ion-releasing compound). The ion-releasing compound is capable of generating a poorly water-soluble salt.

[0165] The ion-releasing compound may be a compound capable of releasing cations, a compound capable of releasing anions, a compound capable of releasing both cations and anions, or a mixture of a compound capable of releasing cations and a compound capable of releasing anions. The ion-releasing compound may contain a compound capable of releasing cations, a compound capable of releasing anions, or a compound capable of releasing cations and a compound capable of releasing anions. Only one type of the ion-releasing compound may be used, or two or more types may be used in combination.

[0166] The ion-releasing compound preferably generates a poorly water-soluble salt upon contact with moisture or the like attached to the ground or a structure. Preferably, the ion-releasing compound releases cations or anions when water or moisture reaches the location where the sealant is placed. Specifically, if the ion-releasing compound is a compound capable of releasing cations, the cations released from the ion-releasing compound preferably react with anions dissolved in moisture or the like to form a poorly water-soluble salt. If the ion-releasing compound is a compound capable of releasing anions, the anions released from the ion-releasing compound preferably react with cations dissolved in moisture or the like to form a poorly water-soluble salt. Furthermore, if the ion-releasing compound is a compound capable of releasing both cations and anions, or a mixture of a compound capable of releasing cations and a compound capable of releasing anions, the cations and anions released from the ion-releasing compound preferably migrate to a medium such as moisture and form a poorly water-soluble salt at the point where they meet.

[0167] The ion-releasing compound may be an inorganic salt, an ion-exchange resin, or an ion complex.

[0168] Examples of the ion-releasing compound include calcium silicate, tricalcium silicate, dicalcium silicate, calcium aluminate, calcium aluminoferrite, calcium hydroxide, calcium oxide, calcium acetate, calcium lactate, barium lactate, calcium sulfate, calcium chloride, calcium nitrate, calcium bicarbonate, sodium hydrogen phosphate, potassium carbonate, potassium bicarbonate, ammonium carbonate, ammonium bicarbonate, sodium carbonate, and sodium bicarbonate. The ion-releasing compound is preferably one of these ion-releasing compounds. These ion-releasing compounds can more effectively produce poorly water-soluble salts.

[0169] Examples of the compound capable of releasing cations include calcium silicate, tricalcium silicate, dicalcium silicate, calcium aluminate, calcium aluminoferrite, calcium hydroxide, calcium oxide, calcium acetate, calcium lactate, barium lactate, calcium sulfate, calcium chloride, calcium nitrate, calcium bicarbonate, etc. The compound capable of releasing cations may be used alone or in combination of two or more.

[0170] The compound capable of releasing cations is preferably calcium silicate, tricalcium silicate, dicalcium silicate, calcium aluminate, calcium aluminoferrite, calcium hydroxide, calcium oxide, calcium acetate, calcium lactate, barium lactate, calcium sulfate, calcium chloride, calcium nitrate, or calcium bicarbonate. When the compound capable of releasing cations is one of the preferred compounds, the effects of the present disclosure can be more effectively exhibited. From the viewpoint of more effectively exhibiting the effects of the present disclosure, the compound capable of releasing cations is more preferably calcium oxide, calcium chloride, calcium nitrate, calcium acetate, calcium lactate, or barium lactate, and even more preferably calcium lactate. From the viewpoint of more effectively exhibiting the effects of the present disclosure, the compound capable of releasing cations is preferably a compound capable of releasing calcium ions, and more preferably an organic acid calcium salt. Examples of the organic acid calcium salt include calcium acetate and calcium lactate.

[0171] Examples of the compound capable of releasing anions include sodium hydrogen phosphate, potassium carbonate, potassium hydrogen carbonate, ammonium carbonate, ammonium hydrogen carbonate, sodium carbonate, sodium hydrogen carbonate, calcium hydrogen carbonate, etc. The compound capable of releasing anions may be used alone or in combination of two or more.

[0172] From the viewpoint of more effectively exerting the effects of the present disclosure, the compound capable of releasing anions is preferably sodium hydrogen phosphate, potassium carbonate, potassium hydrogen carbonate, ammonium carbonate, ammonium hydrogen carbonate, sodium carbonate, sodium hydrogen carbonate, or calcium hydrogen carbonate. From the viewpoint of more effectively exerting the effects of the present disclosure, the compound capable of releasing anions is more preferably sodium hydrogen phosphate, sodium carbonate, or sodium hydrogen carbonate, and even more preferably sodium hydrogen carbonate. From the viewpoint of more effectively exerting the effects of the present disclosure, the compound capable of releasing anions is preferably a compound capable of releasing hydrogen carbonate ions (bicarbonate ions) or carbonate ions.

[0173] Examples of the compound capable of releasing both cations and anions include calcium bicarbonate.

[0174] From the viewpoint of producing the poorly water-soluble salt more efficiently, the sealant is preferably a mixture of a compound capable of releasing cations and a compound capable of releasing anions, and more preferably a mixture of a compound capable of releasing calcium ions and a compound capable of releasing bicarbonate ions or carbonate ions. From the viewpoint of producing the poorly water-soluble salt more efficiently, the sealant preferably contains a compound capable of releasing cations and a compound capable of releasing anions, and more preferably contains a compound capable of releasing calcium ions and a compound capable of releasing bicarbonate ions or carbonate ions.

[0175] Examples of the poorly water-soluble salt include the following compounds: calcium carbonate (specific gravity: 2.71, solubility in water at 20°C: 1.5 x 10 －４ mol / L). Barium carbonate (specific gravity: 4.29, solubility in water at 20°C: 1.25 x 10 －４ mol / L). Calcium phosphate (specific gravity: 3.14, solubility in water at 20°C: 6.5 x 10 －５ mol / L). Iron hydroxide (specific gravity: 3.40, solubility in water at 20°C: 5.0 x 10 －６ mol / L).

[0176] From the viewpoint of more effectively exerting the effects of the present disclosure, the poorly water-soluble salt is preferably calcium carbonate, barium carbonate, calcium phosphate, or iron hydroxide. From the viewpoint of more effectively exerting the effects of the present disclosure, the ion-releasing compound is preferably capable of generating calcium carbonate, barium carbonate, calcium phosphate, or iron hydroxide as the poorly water-soluble salt. From the viewpoint of more effectively exerting the effects of the present disclosure, the poorly water-soluble salt is preferably calcium carbonate. From the viewpoint of more effectively exerting the effects of the present disclosure, the ion-releasing compound is preferably capable of generating calcium carbonate as the poorly water-soluble salt.

[0177] The ion-releasing compound may be particulate. The ion-releasing compound may be spherical, may have a shape other than spherical, or may be flat. The ion-releasing compound is preferably spherical.

[0178] The particle diameter of the ion-releasing compound is preferably 1.0 μm or more, more preferably 5.0 μm or more, even more preferably 10 μm or more, and preferably 1000 μm or less, more preferably 500 μm or less, even more preferably 150 μm or less, and particularly preferably 100 μm or less. When the particle diameter of the ion-releasing compound is equal to or greater than the lower limit, the ion-releasing compound is well coated with the coating agent described below, thereby improving the dispersibility of the ion-releasing compound in the sealant and the sealed product. Furthermore, when the particle diameter of the ion-releasing compound is equal to or greater than the lower limit, the viscosity of the sealant when filling the sealed area is improved, thereby improving the placement of the sealant. When the particle diameter of the ion-releasing compound is equal to or less than the upper limit, the dispersibility of the ion-releasing compound in the sealant and the sealed product is improved.

[0179] The particle size of the ion-releasing compound is preferably an average particle size. The average particle size indicates a number-average particle size. The average particle size of the ion-releasing compound is determined by observing 50 random ion-releasing compounds with an electron microscope or an optical microscope and calculating the average value.

[0180] In the sealant, the surface of the ion-releasing compound may be coated with a coating agent. The ion-releasing compound may be an inclusion of a microcapsule. When the ion-releasing compound is an inorganic salt, the surface of the ion-releasing compound in the sealant is preferably coated with a coating agent. When the ion-releasing compound is an inorganic salt, the sealant preferably contains microcapsules containing the ion-releasing compound as an inclusion. When the surface of the ion-releasing compound is coated with a coating agent or the ion-releasing compound is an inclusion of a microcapsule, the timing and amount of release of cations or anions from the ion-releasing compound can be controlled.

[0181] The ion-releasing compound coated with the coating agent is preferably capable of releasing cations or anions when moisture such as water or humidity comes into contact with the sealant (or sealed object) and the moisture diffuses and penetrates into the coating agent. The ion-releasing compound coated with the coating agent may be capable of releasing cations or anions from voids in the coating agent. The ion-releasing compound coated with the coating agent may be capable of diffusing into the coating agent and releasing cations or anions. In these cases, the timing and amount of cations or anions released from the ion-releasing compound can be more effectively controlled.

[0182] The microcapsules are preferably capable of releasing the ion-releasing compound. The membranes constituting the microcapsules preferably disintegrate upon contact with water or moisture, allowing for better control of the timing and amount of release of cations or anions from the ion-releasing compound.

[0183] The material of the membrane constituting the microcapsules and the material of the coating agent for coating the surface of the ion-releasing compound can be appropriately selected depending on the type of the ion-releasing compound. The material of the membrane constituting the microcapsules and the material of the coating agent for coating the surface of the ion-releasing compound preferably contain a coupling agent or a resin. In this case, the dispersibility of the ion-releasing compound in the sealant and the sealed object can be improved, and the timing and amount of release of cations or anions can be well controlled. Furthermore, the thickness of the membrane constituting the microcapsules can be made uniform, and the surface of the ion-releasing compound can be uniformly coated with the coating agent.

[0184] Examples of the coupling agent include a silane coupling agent and a titanium coupling agent.

[0185] Examples of the resin include water-soluble resins, thermoplastic resins, and curable resins. Only one type of resin may be used, or two or more types may be used in combination. The resin contained in the sealant and the resin contained in the material of the coating agent may be the same or different.

[0186] Examples of the water-soluble resin include polyvinyl alcohol, polylactic acid resin (PLA resin), poly(meth)acrylic acid, poly(meth)acrylamide, polyvinylpyrrolidone, polyethylene oxide, and methyl cellulose.

[0187] Examples of the thermoplastic resin and the curable resin include the thermoplastic resins and curable resins described above.

[0188] From the viewpoint of better controlling the timing and amount of release of cations or anions from the ion-releasing compound, the resin contained in the material of the coating agent preferably contains a thermoplastic resin, more preferably contains a polyolefin resin, further preferably contains an ethylene-vinyl acetate copolymer, and particularly preferably is an ethylene-vinyl acetate copolymer.

[0189] The thickness of the membrane constituting the microcapsules and the thickness of the coating layer of the coating agent are not particularly limited. From the viewpoint of better controlling the timing and amount of release of cations or anions from the ion-releasing compound, the thickness of the membrane constituting the microcapsules and the thickness of the coating layer of the coating agent are preferably 1 μm or more, more preferably 5 μm or more, and preferably 1000 μm or less, more preferably 200 μm or less.

[0190] The content of the ion-releasing compound in 100% by weight of the sealant is preferably 3% by weight or more, more preferably 5% by weight or more, even more preferably 10% by weight or more, particularly preferably 20% by weight or more, and preferably 70% by weight or less, more preferably 50% by weight or less, even more preferably 45% by weight or less, particularly preferably 40% by weight or less. When the content of the ion-releasing compound is above the above-mentioned lower limit and below the above-mentioned upper limit, cations or anions are more effectively released, and poorly water-soluble salts are efficiently produced. As a result, the sealed area and its surroundings are more densified, and the structure can be maintained in a stable state for a longer period of time. When the content of the ion-releasing compound is below the above-mentioned upper limit, the appearance of the structure after sealing with the sealant can be improved, and the strength of the sealed area and its surroundings can be increased.

[0191] The content of the ion-releasing compound is preferably 3 parts by weight or more, more preferably 5 parts by weight or more, even more preferably 10 parts by weight or more, particularly preferably 20 parts by weight or more, and preferably 200 parts by weight or less, more preferably 100 parts by weight or less, and even more preferably 70 parts by weight or less, per 100 parts by weight of the resin. When the content of the ion-releasing compound is above the lower limit and below the upper limit, cations or anions are released more effectively, and poorly water-soluble salts are produced well. As a result, the sealed area and its surroundings are further densified, allowing the structure to be maintained in a stable state for a longer period of time. When the content of the ion-releasing compound is below the upper limit, the viscosity of the sealant when filling the area to be sealed is improved, thereby improving the placement of the sealant.

[0192] The total content of the ion-releasing compound and the coating agent in 100% by weight of the sealant is preferably 3% by weight or more, more preferably 5% by weight or more, and preferably 70% by weight or less, more preferably 50% by weight or less. When the total content of the ion-releasing compound and the coating agent is above the lower limit and below the upper limit, cations or anions are released more effectively, and poorly water-soluble salts are produced efficiently. As a result, the sealed area and its surroundings are further densified, allowing the structure to be maintained in a stable state for a longer period of time. When the total content of the ion-releasing compound and the coating agent is below the upper limit, the viscosity of the sealant when filled into the area to be sealed is improved, thereby improving the placement of the sealant.

[0193] <Other Components> The sealant may contain other components in addition to the resin, the ion-releasing compound, and the coating agent, as necessary. Examples of the other components include a reaction catalyst, a reaction accelerator, a crosslinking agent, a water absorbent, a foam stabilizer, an antioxidant, and a colorant.

[0194] (Structure and method for manufacturing a structure) A structure can be obtained using the sealant according to the present disclosure. The structure preferably includes an object to be sealed having a portion to be sealed, and a sealant disposed on the portion to be sealed. The sealant is preferably formed from the sealant. The sealant may be formed by curing a resin (curable resin) in the sealant. The sealant may be a cured product of the sealant. The sealant may be formed by extrusion molding or injection molding the sealant. The sealant may be a molded product of the sealant.

[0195] The ion-releasing compound in the sealant (in the cured product of the sealant or in the molded product of the sealant) is preferably dispersed in the resin or in the cured product of the curable resin.

[0196] The sealing material may be a waterproof sheet or a waterproof member. The sealing material may be in the form of a sheet. When the sealing material is in the form of a sheet, the thickness of the sealing material is preferably 0.05 mm or more, more preferably 0.1 mm or more, even more preferably 0.5 mm or more, and preferably 5 mm or less, more preferably 3 mm or less, and even more preferably 2 mm or less. When the thickness of the sealing material is equal to or greater than the above-mentioned lower limit and equal to or less than the above-mentioned upper limit, the waterproofness of the sealed area and its surroundings can be improved.

[0197] The method for manufacturing the structure preferably includes (1A) a disposing step of disposing the sealant on a portion to be sealed of an object to be sealed, and (2A) a curing step of curing the resin in the sealant. The method for manufacturing the structure may also include (1B) a molding step of extrusion molding or injection molding the sealant to form a sealed object, and (2B) a disposing step of disposing the sealant on a portion to be sealed of an object to be sealed.

[0198] The method for manufacturing the structure described above provides a structure having a sealing material disposed in the sealing target portion, and the structure can be densified in the sealed area and its surroundings, and can be maintained in a stable state for a long period of time.

[0199] From the viewpoint of more effectively achieving the effects of the present disclosure, it is preferable that the object to be sealed includes concrete. From the viewpoint of more effectively achieving the effects of the present disclosure, it is preferable that the object to be sealed is a concrete structure. The object to be sealed may include the ground. The part to be sealed may be a void or the outer surface of the object to be sealed. It is preferable that the part to be sealed is a void in the concrete structure or the outer surface of the concrete structure. The void in the concrete structure may be a crack in the concrete structure, a gap at a joint between members in the concrete structure, or a boundary between the concrete structure and the ground. Examples of the outer surface of the concrete structure include the outer surface of an insulator (grout portion) arranged on the outer surface of a pipe or the like.

[0200] The sealant may be used by filling the area to be sealed. The method for filling the area to be sealed with the sealant is not particularly limited. Examples of methods for filling the area to be sealed with the sealant include forming an injection port in the structure that penetrates from the front to the back of the structure, and injecting the sealant into the area to be sealed through the injection port. The amount of the sealant injected can be changed appropriately depending on the size of the area to be filled (the area to be sealed), etc. The sealant may be filled by a backfilling method.

[0201] The pressure when filling (injecting) the sealant can be changed as appropriate depending on the viscosity of the sealant, the size of the area to be filled (the area to be sealed), etc. The sealant may be filled (injected) at high pressure or low pressure. When filling at high pressure, the pressure is preferably 0.5 MPa or more and 24 MPa or less. When filling at low pressure, the pressure is preferably 0.01 MPa or more and 0.5 MPa or less. From the viewpoint of improving the injectability of the sealant into the fine details of the area to be sealed, the pressure when injecting the sealant is preferably 0.1 MPa or more and 4 MPa or less.

[0202] An example of a method for manufacturing a structure using a sealant will be described. First, a hole is drilled at a predetermined angle from the front to the back of the structure to form an injection port. Next, the injection plug of the sealant supply device is connected to the injection gun. After that, a compressor is used to fill (inject) the sealant through the injection port into the area to be sealed (placement process). Before the placement process, an injection plate may be installed on the front side of the structure to cover the periphery of the injection plug in order to prevent the sealant from leaking out of the front of the structure.

[0203] Next, if the resin in the sealant contains a curable resin, the curable resin in the sealant is cured (curing step). In this way, a structure can be obtained. The structure includes a cured product of the sealant as a filler filled in the sealing target portion. The structure is formed with the cured product of the sealant.

[0204] The cured product of the sealant preferably contains a cured product of the resin (curable resin) and the ion-releasing compound. The ion-releasing compound in the cured product of the sealant is a compound capable of releasing cations or anions. The ion-releasing compound in the cured product of the sealant is capable of generating a poorly water-soluble salt inside or on the surface of the cured product of the sealant. The ion-releasing compound in the cured product of the sealant is preferably dispersed in the cured product of the resin (curable resin).

[0205] In the above structure, the sealed area and its surroundings can be densified, and can be maintained in a stable state for a long period of time.

[0206] The above descriptions regarding the sealing material, the structure, and the method for manufacturing the structure can also be applied to concretion accelerators and ground improvement methods.

[0207] (Technology for controlling underground and surface water) The technology of the present disclosure can be used to control underground and surface water.

[0208] A control method according to one aspect of the present disclosure includes the steps of providing an ion supply material containing at least one of a first compound capable of generating cations that constitute a poorly soluble salt and a second compound capable of generating anions that constitute the poorly soluble salt, and an acid that donates protons, in an area where water is present underground and / or on the surface of the earth, and changing at least one of the flow rate, flow direction, and retention amount of the water by precipitating the poorly soluble salt around the ion supply material.

[0209] The control method may further include a step of providing a hole in the region, wherein the step of providing the ion supply material includes a step of providing the ion supply material inside the hole, and the precipitation of the poorly soluble salt inside and around the hole may change at least one of the flow rate, flow direction, and retention amount of the water inside and around the hole.

[0210] The ion supply material may be provided upstream of the region where the inflow of water should be reduced. The ion supply material may be provided downstream of the region where the outflow of water should be reduced. The ion supply material may be provided along a flow path that guides the water. The ion supply material may be present at a plurality of locations in the region, and at least one of the flow rate, flow direction, and retention amount of the water may be changed by the poorly soluble salt precipitating between adjacent ion supply materials. At least a portion of the poorly soluble salt precipitated between adjacent ion supply materials may unite to form a wall.

[0211] A plurality of the holes may be provided, and the intervals between the holes may be determined based on the diffusion coefficient of at least one of the cations and the anions at the locations where the plurality of holes are provided. The intervals between the holes may be determined based on the width L (cm) of the reaction edge of the hardly soluble salt formed around the hole, the speed V (cm / s) at which the reaction edge is formed, and the diffusion coefficient D (cm ２ / s) based on the relationship D=VL.

[0212] The hardly soluble salt may be calcium carbonate, and when calcium carbonate precipitates, strontium contained in the water may be taken up.

[0213] The ion supply material may include a base material and at least one of the first compound and the second compound mixed in the base material.

[0214] A pH adjuster may be provided inside the hole to increase the pH of the groundwater.

[0215] A reinforcement method according to one aspect of the present disclosure includes the steps of providing, in at least one of the underground and the surface of the earth, an ion supply material containing at least one of a first compound capable of generating cations that constitute a poorly soluble salt and a second compound capable of generating anions that constitute the poorly soluble salt, and an acid that donates protons, and reinforcing at least one of the underground and the surface of the earth by precipitating the poorly soluble salt around the ion supply material.

[0216] A purification method according to one aspect of the present disclosure includes the steps of providing, at least one of underground and on the surface of the earth, an ion supply material containing at least one of a first compound capable of generating cations that constitute a poorly soluble salt and a second compound capable of generating an anion that constitutes the poorly soluble salt, and an acid that donates protons; and reducing harmful ions present around the ion supply material by generating and precipitating the poorly soluble salt with the cations or anions.

[0217] A structure according to one embodiment of the present disclosure comprises an ion supply material present in an area where water is present in at least one of the underground and the surface of the earth, the ion supply material including at least one of a first compound capable of generating cations that constitute a poorly soluble salt and a second compound capable of generating anions that constitute the poorly soluble salt, an acid that donates protons, and the poorly soluble salt present around the ion supply material.

[0218] The ion supplying material may be present inside pores present in the region.

[0219] A method for repairing a workpiece according to an embodiment of the present disclosure includes adding the ion supplying material and an acid that donates protons to the vicinity of the sparingly soluble salt.

[0220] The method for repairing a workpiece may include the steps of providing a new hole in the vicinity of the hole, and providing the ion supplier and an acid that donates protons inside the new hole.

[0221] The water that can be controlled by the control method of one embodiment of the present disclosure is all water that exists underground or on the ground, regardless of whether it is seawater or freshwater. The control method of the present disclosure can control water that has infiltrated into the ground from rivers, ponds, lakes, waterways, seas, canals, etc., water that has been generated in large quantities on the ground surface due to rainfall, typhoons, tornadoes, river flooding, etc., water that exists in rivers, ponds, lakes, waterways, seas, canals, etc., and water that has been generated in large quantities on the ground surface due to rainfall, typhoons, tornadoes, river flooding, etc.

[0222] When controlling groundwater, seepage water, etc. present underground, the ion supplying material may be provided underground, such as in soil, ground, bedrock, or the seabed. When controlling river water, seawater, etc. present on the ground's surface, the ion supplying material may be provided on the ground or underground in contact with the river water, seawater, etc. As will be described later, ions supplied from the ion supplying material diffuse into the surroundings and precipitate sparingly soluble salts, so it is desirable to provide the ion supplying material in a location where the ions supplied from the ion supplying material can diffuse into the surroundings.

[0223] (Technique for filling voids in contact portions) The technique of the present disclosure can be used to fill voids in contact portions such as tunnels.

[0224] An ion supply material according to one embodiment of the present disclosure includes ions capable of forming calcium carbonate to fill voids in contact areas between a base material for forming a structure and the surrounding rock mass or stratum, and an acid that donates protons, and the supplied ions diffuse into the voids in the contact areas to form calcium carbonate with counter ions present in the voids, thereby filling the voids in the contact areas with calcium carbonate.

[0225] The ion supplying material may gradually release the ions. The ion supplying material may include a salt of the ions that is readily soluble in water. The ions may include at least one of bicarbonate ions, carbonate ions, and calcium ions. The ion supplying material may supply counter ions that can form calcium carbonate with the ions. The ion supplying material may gradually release the counter ions.

[0226] A sealing composition according to one embodiment of the present disclosure includes ions capable of forming calcium carbonate for filling voids in contact areas between a base material for forming a structure and the surrounding rock mass or stratum, and an acid that donates protons, and includes an ion source for filling the voids in the contact areas with calcium carbonate by diffusing the supplied ions into the voids in the contact areas and forming calcium carbonate with counter ions present in the voids.

[0227] A sealing composition according to an embodiment of the present disclosure includes an ion donor that slowly releases ions capable of forming a sparingly soluble compound, and an acid that donates protons.

[0228] (Second embodiment) As a second embodiment of the present disclosure, a technology will be described in which concrete debris generated when demolishing a building made of concrete or the like is used in the concretion accelerator or ground improvement method of the first embodiment.

[0229] In demolition work of buildings using specific construction materials such as concrete, or new construction work using specific construction materials in its construction, which exceeds a specified standard in scale, the Act on Recycling of Materials Used in Construction Works requires the implementation of sorted demolition and recycling. The concrete debris (concrete fragments and similar waste materials) generated during demolition work of such buildings or new construction work is usually crushed by a crusher or the like and reused as aggregate or crushed stone. A large amount of powder is generated in the process of recycling concrete debris, but at present it is discarded without being reused. This powder is calcium hydroxide (Ca(OH)) generated by the hydration reaction of calcium oxide (CaO) inside the concrete. ２ ) contains a lot of

[0230] Therefore, in this embodiment, the powder generated when processing concrete debris is used as an ion source that supplies calcium ions in the concretion accelerator and ground improvement method of the first embodiment. This allows the powder that would have been discarded to be reused, reducing the amount of waste and further promoting the effective use of concrete debris. In addition, the manufacturing costs of the concretion accelerator and the costs required for ground improvement can be significantly reduced.

[0231] Although calcium hydroxide does not have a high solubility in water, the coexistence of an acid can promote the supply of calcium ions through a neutralization reaction. When the ion supply material comes into contact with water, the calcium contained therein is not immediately released as calcium ions, but is gradually released through a neutralization reaction with the acid, allowing the concretion effect to be maintained for a long period of time.

[0232] The concretion accelerator according to the second embodiment of the present disclosure includes a powder containing a calcium compound, and is equipped with an ion supplier that gradually releases calcium ions, and an acid that donates protons.

[0233] The powder may include powder generated during the processing of building materials containing calcium compounds. Building materials containing calcium compounds may include concrete, cement, lime, gypsum, concrete debris, etc. The processing of building materials may include the manufacturing, processing, and recycling of building materials, and the construction, demolition, and renovation of structures containing building materials. The recycling process may include crushing, sorting, and sizing of building materials.

[0234] The powder may include calcium hydroxide.

[0235] The acid may be the acid described in the first embodiment. The concretion accelerator may include a solid acid.

[0236] The concretion accelerator may include a base material coated with a powder and an acid. The base material may be the base material described in the first embodiment. The base material may include a resin.

[0237] The concretion accelerator may include a second ion supplier that supplies at least one of carbonate ions and bicarbonate ions. This allows calcium carbonate to be produced efficiently, thereby accelerating concretion.

[0238] The weight ratio of the ion supplying material may be greater than the weight ratio of the acid. Alternatively, the ion supplying material and the acid may be contained in the concretion accelerator in a separate state. This allows the ground to be concreted efficiently.

[0239] In the concretion accelerator, the ion donor and the acid may be contained in a separated state.

[0240] The concretion accelerator may include a water-insoluble filler. The filler may be made of a material such as glass, ceramics, minerals, carbon, or metal. The filler may have a fibrous, scaly, or particulate shape. This can improve the strength of the area where the concretion accelerator is installed. Furthermore, the strength can be maintained even after the calcium compound contained in the concretion accelerator is eluted.

[0241] The specific gravity of the concretion accelerator may be equal to or greater than 1. This makes it possible to prevent separation before hardening when the concretion accelerator is mixed with sand, crushed stone, cement, or the like and used as a grout material or concrete material.

[0242] 6 is a flowchart showing the steps of a method for utilizing building materials according to a second embodiment of the present disclosure. Building materials, such as concrete debris generated during demolition, new construction, and renovation of buildings, are collected from construction sites and processed at recycling facilities (S30). The concrete debris recycling process includes crushing, sorting, and sizing of the concrete debris. The recycled concrete debris is used as recycled crushed runoff, recycled sand, recycled aggregate, and the like. Powder generated during this recycling process that is not used as a recyclable resource is collected (S32).

[0243] The collected powder is pre-treated (S34). The pre-treatment includes crushing the powder, sizing, removing foreign matter, gravity sorting, washing with water, drying, etc. The pre-treatment may be omitted.

[0244] The powder and acid are dispersed in a base material such as resin (S36). When the base material is resin, the powder and acid may be dispersed in a liquid state obtained by heating and melting the resin or dissolving the resin in a solvent. At this time, an antioxidant, a heat stabilizer, a radical scavenger, or the like may be added to prevent the calcium compound, acid, resin, or the like contained in the powder from being denatured by heating or the solvent. The base material may be any combination of resin, cement, or the like.

[0245] A second ion supplying material for supplying at least one of carbonate ions and bicarbonate ions may be further dispersed in the base material. The second ion supplying material may include a carbonate such as sodium carbonate, potassium carbonate, magnesium carbonate, or ammonium carbonate, or a bicarbonate such as sodium bicarbonate, potassium bicarbonate, magnesium bicarbonate, or ammonium bicarbonate.

[0246] A concretion accelerator containing powder, acid, and a base material is formed (S38). The form of the concretion accelerator may be the same as that of the first embodiment. When forming the concretion accelerator into a powder form, a bulk body or coarse powder may be pulverized using a pulverizer, or the concretion accelerator in a liquid state may be powdered using a spray drying method or the like. The powdered particles may be sorted based on their specific gravity, or particles that dissolve in water in a short time may be removed by washing with water and drying. When forming the concretion accelerator into a sheet form, the concretion accelerator in a liquid state may be cast onto a flat surface, or may be formed using an inflation method, casting method, or the like.

[0247] The concretion accelerator is supplied to the ground (S40). The method of supplying the concretion accelerator to the ground may be the same as that of the first embodiment. Alternatively, the powder alone may be dispersed in a base material to form an ion supply material, and the ion supply material and the acid may be supplied to the ground separately.

[0248] Any combination of the technology described in the first embodiment and the technology described in the second embodiment is also effective as an embodiment of the present disclosure.

[0249] The second embodiment is as follows. [Aspect 1] A concretion accelerator comprising: an ion supplier containing a powder containing a calcium compound and gradually releasing calcium ions; and an acid that donates protons. [Aspect 2] The concretion accelerator according to Aspect 1, in which the powder contains calcium hydroxide. [Aspect 3] The concretion accelerator according to Aspect 1, in which the powder contains powder generated during the treatment of a building material containing a calcium compound. [Aspect 4] The concretion accelerator according to any one of Aspects 1 to 3, in which the acid contains a solid acid. [Aspect 5] The concretion accelerator according to any one of Aspects 1 to 4, in which a base material coats the powder and the acid. [Aspect 6] The concretion accelerator according to Aspect 5, in which the base material contains a resin. [Aspect 7] The concretion accelerator according to any one of Aspects 1 to 6, in which a second ion supplier supplies at least one of carbonate ions and bicarbonate ions. [Aspect 8] The concretion accelerator according to any one of Aspects 1 to 7, wherein the weight ratio of the ion supply material is greater than the weight ratio of the acid. [Aspect 9] The concretion accelerator according to any one of Aspects 1 to 8, wherein the ion supply material and the acid are contained in a separated state. [Aspect 10] The concretion accelerator according to any one of Aspects 1 to 9, comprising a water-insoluble filler. [Aspect 11] The concretion accelerator according to Aspect 10, wherein the filler contains at least one of glass, ceramics, carbon, metal, and mineral. [Aspect 12] The concretion accelerator according to Aspect 10 or 11, wherein the filler has a fibrous, scaly, or particulate shape. [Aspect 13] The concretion accelerator according to any one of Aspects 1 to 12, wherein the specific gravity of the concretion accelerator is 1 or more. [Aspect 14] A method for producing a concretion accelerator, comprising a step of dispersing a powder containing a calcium compound and a proton-donating acid in a matrix. [Aspect 15] The method according to aspect 14, wherein the powder comprises calcium hydroxide. [Aspect 16] The method according to aspect 14 or 15, wherein the powder comprises powder generated during processing of a building material containing a calcium compound.[Embodiment 17] A method comprising a step of utilizing powder generated during processing of a building material containing a calcium compound to supply calcium ions to the ground.

[0250] The present disclosure has been described above based on examples. These examples are merely illustrative, and it will be understood by those skilled in the art that various modifications are possible in the combination of the components and processing steps, and that such modifications are also within the scope of the present disclosure.

[0251] The present disclosure is applicable to concretion accelerators, ground improvement methods, and sealing materials.

[0252] 1 Ground, 2 First ion supply material injection hole, 3 First ion supply material, 4 Second ion supply material injection hole, 5 Second ion supply material.

Claims

1. A concretion accelerator comprising: an ion supplier that gradually releases ions capable of forming a sparingly soluble compound; and an acid that donates protons.

2. The concretion accelerator according to claim 1, wherein the ions include at least one of calcium ions, carbonate ions, and bicarbonate ions.

3. The concretion accelerator according to claim 1, wherein the acid includes a solid acid.

4. The concretion accelerator according to claim 1, wherein the acid does not contain phosphoric acid.

5. The concretion accelerator according to any one of claims 1 to 4, comprising a base material that coats the ions and the acid.

6. The concretion accelerator according to claim 5, wherein the base material contains calcium ions, and the ions contain carbonate ions or bicarbonate ions.

7. The concretion accelerator according to claim 6, wherein the base material contains cement.

8. The concretion accelerator according to claim 5, wherein the base material contains a resin.

9. A concretion accelerator according to any one of claims 1 to 4, having a permeability coefficient greater than the permeability coefficient of the ground on which the concretion accelerator is applied.

10. A concretion accelerator according to any one of claims 1 to 4, having a hydraulic conductivity smaller than the hydraulic conductivity of the ground on which the concretion accelerator is applied.

11. A concretion accelerator according to any one of claims 1 to 4, wherein the weight ratio of the ion supplying material is greater than the weight ratio of the acid.

12. The concretion accelerator according to any one of claims 1 to 4, wherein the ion supplying material and the acid are contained in a separated state.

13. The concretion accelerator according to any one of claims 1 to 4, which contains a compound that generates carbon dioxide through a chemical reaction.

14. A concretion accelerator according to any one of claims 1 to 4, wherein the compound contains at least one of a carbonate ester and a cyclic carbonate.

15. The concretion accelerator according to any one of claims 1 to 4, comprising an additive containing at least one of a release agent, a lubricant, a plasticizer, a thickener, a thixotropic agent, a viscosity reducer, a crystal nucleating agent, a pigment, a dye, a compatibilizer, a surface treatment agent, an antioxidant, and an ultraviolet absorber.

16. A method comprising: a step of reducing the permeability of ground; and a step of supplying an ion supplying material to the ground to supply ions capable of forming a sparingly soluble compound.

17. A method comprising: a step of reducing the permeability of ground; and a step of supplying to the ground a concretion promoter comprising an ion supplier for supplying ions capable of forming a sparingly soluble compound and an acid for donating protons.

18. A method comprising the steps of: obtaining an index representing the permeability of the ground; and, if the permeability of the ground is such that ions capable of forming sparingly soluble compounds supplied to the ground may become supersaturated, supplying an ion supply material to the ground for supplying the ions.

19. The method according to claim 18, comprising: a step of reducing the permeability of the ground when the permeability of the ground is such that the ions supplied to the ground are diluted before they become supersaturated; and a step of supplying the ion supply material to the ground whose permeability has been reduced so that the ions can become supersaturated.

20. The method of claim 16, 17, or 19, wherein the step of reducing the permeability of the ground includes the step of supplying an improvement material to the ground to reduce the permeability of the ground.

21. The method according to claim 20, wherein the improving material includes the ion supplying material.

22. The permeability of the soil is such that the ions capable of forming poorly soluble compounds supplied to the soil can be supersaturated. The permeability coefficient is 10 －２ The method according to claim 18 or 19, wherein the speed is equal to or less than m / sec.

23. A method according to any one of claims 16 to 19, wherein the step of supplying the ion supply material to the ground includes the steps of: supplying one of the cations and anions that form the poorly soluble compound to the ground; and supplying the other of the cations and anions that form the poorly soluble compound to the ground.

24. The method of claim 23, wherein the diffusion rates of the cations and the anions are different.

25. The method of claim 23, wherein the cations include calcium ions and the anions include carbonate ions or bicarbonate ions.

26. A method comprising the steps of: supplying to the ground an ion supplier that slowly releases ions capable of forming a sparingly soluble compound; and supplying to the ground an acid that donates protons.

27. A method comprising the steps of: reducing the permeability of ground; supplying the ground with an ion supplying material that slowly releases ions capable of forming a sparingly soluble compound; and supplying the ground with an acid that donates protons.

28. A sealing material comprising: an ion supplier that gradually releases ions capable of forming a sparingly soluble compound; and an acid that donates protons.

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